U.S. patent application number 14/784914 was filed with the patent office on 2016-05-26 for quinone based nitric oxide donating compounds for ophthalmic use.
The applicant listed for this patent is NICOX SCIENCE IRELAND. Invention is credited to Nicoletta ALMIRANTE, Elena BASTIA, Gael RONSIN, Laura STORONI.
Application Number | 20160145192 14/784914 |
Document ID | / |
Family ID | 48142658 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160145192 |
Kind Code |
A1 |
ALMIRANTE; Nicoletta ; et
al. |
May 26, 2016 |
QUINONE BASED NITRIC OXIDE DONATING COMPOUNDS FOR OPHTHALMIC
USE
Abstract
The present invention relates to nitric oxide donor compounds
having a quinone based structure, to processes for their
preparation and to their use in the treatment and/or prophylaxis of
glaucoma and ocular hypertension.
Inventors: |
ALMIRANTE; Nicoletta;
(Milano, IT) ; STORONI; Laura; (Cesano Maderno,
IT) ; RONSIN; Gael; (Milano, IT) ; BASTIA;
Elena; (Milano, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NICOX SCIENCE IRELAND |
Dublin 2 |
|
IE |
|
|
Family ID: |
48142658 |
Appl. No.: |
14/784914 |
Filed: |
April 14, 2014 |
PCT Filed: |
April 14, 2014 |
PCT NO: |
PCT/EP2014/057515 |
371 Date: |
October 15, 2015 |
Current U.S.
Class: |
514/534 ;
514/529; 560/126; 560/51; 560/53 |
Current CPC
Class: |
A61K 31/216 20130101;
C07C 2601/16 20170501; A61K 31/215 20130101; A61K 9/0048 20130101;
A61K 45/06 20130101; A61P 29/00 20180101; C07C 203/00 20130101;
A61P 27/02 20180101; A61P 27/06 20180101; C07C 2602/10 20170501;
C07C 203/04 20130101; A61P 43/00 20180101 |
International
Class: |
C07C 203/04 20060101
C07C203/04; A61K 9/00 20060101 A61K009/00; A61K 45/06 20060101
A61K045/06; A61K 31/215 20060101 A61K031/215; A61K 31/216 20060101
A61K031/216 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2013 |
EP |
13164236.5 |
Claims
1. A compound of formula (I) ##STR00061## or stereoisomers thereof,
wherein: R.sub.1 is selected from H, methyl, methoxy; R.sub.2 is H
or methyl; R.sub.3 is selected from H, methyl, methoxy; or R.sub.1
and R.sub.3 together form --CH.dbd.CH--CH.dbd.CH--; R.sub.4 and
R.sub.5 are methyl and n is 1, or R.sub.4 is H, R.sub.5 is selected
from phenyl, para-fluorophenyl, para-methoxyphenyl,
para-isopropylphenyl, para-trifluoromethyl phenyl or
para-methylphenyl and n is 2; m is an integer from 1 to 10; p is 0
or 1; R.sub.6 is H or methyl.
2. A compound of formula (I) according to claim 1 wherein R.sub.2
is methyl; R.sub.4 and R.sub.5 are methyl and n is 1.
3. A compound of formula (I) according to claim 1 wherein R.sub.2
is methyl; R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl or para-methylphenyl and n is 2.
4. A compound of formula (I) according to claim 2 wherein R.sub.1
and R.sub.3 are methyl.
5. A compound of formula (I) according to claim 2 wherein R.sub.1
and R.sub.3 are methoxy.
6. A compound of formula (I) according to claim 2 wherein R.sub.1
and R.sub.3 together form --CH.dbd.CH--CH.dbd.CH--.
7. A compound of formula (I) according to claim 2 wherein R.sub.1
is methyl and R.sub.3 is methoxy.
8. A compound of formula (I) according to claim 2 wherein R.sub.1
is methoxy and R.sub.3 is methyl.
9. A compound of formula (I) according to claim 4 wherein p is 0
and R.sub.6 is H.
10. A compound of formula (I) according to claim 4 wherein p is
1.
11. A compound of formula (I) according to claim 3 wherein R.sub.1
and R.sub.3 are methyl.
12. A compound of formula (I) according to claim 3 wherein R.sub.1
and R.sub.3 are methoxy.
13. A compound of formula (I) according to claim 3 wherein R.sub.1
and R.sub.3 together form --CH.dbd.CH--CH.dbd.CH--.
14. A compound of formula (I) according to claim 3 wherein R.sub.1
is methyl and R.sub.3 is methoxy.
15. A compound of formula (I) according to claim 3 wherein R.sub.1
is methoxy and R.sub.3 is methyl.
16. A compound of formula (I) according to claim 11 wherein p is 0
and R.sub.6 is H.
17. A compound of formula (I) according to claim 11 wherein p is
1.
18. A compound of formula (I) according to claim 1 selected from:
4-(nitrooxy)butyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 1); 6-(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 2); 6-(nitrooxy)hexyl
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 3); 4-(nitrooxy)butyl
3-methyl-3-(3-methyl-1,4-dioxo-1,4-dihydro
naphthalene-2-yl)butanoate (Compound 4); 6-(nitrooxy)hexyl
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butan-
oate (Compound 5); 4-(nitrooxy)butyl
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 6); 4-(nitrooxy)butyl
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butan-
oate (Compound 7); (5S,6R)-5,6-bis(nitrooxy)heptyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxo
cyclohexa-1,4-dienyl)butanoate (Compound 8); 4-(nitrooxy)butyl
4-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-4-phenylbutanoat-
e (Compound 9); 5,6-bis(nitrooxy)hexyl-3-methyl
3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 10) 5,6-bis(nitrooxy)hexyl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e (Compound 11) 4-(nitrooxy)butyl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e (Compound 12) 5,6-bis(nitrooxy)hexyl
4-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-4-phenylbutanoat-
e (Compound 13) 5,6-bis(nitrooxy)hexyl
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 14) (S)-5,6-bis(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 15) (R)-5,6-bis(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 16)
(S)-5,6-bis(nitrooxy)hexyl-3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1-
,4-dienyl)-3-methylbutanoate (Compound 17), and stereoisomers
thereof.
19. A compound of formula (I) according to claim 1 for use as
medicament.
20. A compound of formula (I) according to claim 1 for use in
treating hypertensive glaucoma, normotensive glaucoma, secondary
glaucoma and ocular hypertension
21. A compound according to claim 1 for use in treating age related
macular degeneration, diabetic retinopathy, macular degeneration,
inflammatory retinal disease, uveitis.
22. An ophthalmic composition comprising a compound of formula (I)
according to claim 1 and at least an ophthalmically acceptable
component and/or ophthalmically acceptable vehicle.
23. A composition comprising a compound of formula (I) according to
claim 1 and one or more further active ingredients selected from
alpha adrenergic agonists, beta blockers, carbonic anhydrase
inhibitors, prostaglandin analogs, non-steroidal anti-inflammatory
drugs, or a steroidal anti-inflammatory drugs.
24. A composition according to claim 23 for use in treating
hypertensive glaucoma, normotensive glaucoma, secondary glaucoma
and ocular hypertension.
25. A composition according to claim 22 for use in treating age
related macular degeneration, diabetic retinopathy, macular
degeneration, inflammatory retinal disease, uveitis.
26. An ophthalmic composition comprising a composition according to
claim 23 and at least an ophthalmically acceptable component and/or
ophthalmically acceptable vehicle.
Description
[0001] The present invention relates to nitric oxide donor
compounds of formula (I) and their use in the treatment and/or
prophylaxis of glaucoma and ocular hypertension.
[0002] The present invention also relates to combinations
comprising nitric oxide donor compounds of formula (I) and one or
more further active ingredients for the use in the treatment and/or
prophylaxis of glaucoma and ocular hypertension.
[0003] Glaucoma, including normotensive and hypertensive glaucoma,
is a disease of the eye characterized by a progressive loss of
visual field due to irreversible damage to the optic nerve to the
point where, if untreated, may result in total blindness.
Hypertensive glaucoma occurs when an imbalance in production and
drainage of fluid in the eye (aqueous humor) increases eye pressure
to unhealthy levels.
[0004] Conversely, normotensive glaucoma occurs despite the
intraocular pressure is kept to reasonably low levels.
[0005] The loss of visual field, in one form of primary open angle
glaucoma (POAG), is associated with a sustained increase in the
intraocular pressure of the diseased eye. Moreover, elevated
intraocular pressure without visual field loss is thought to be
indicative of the early stages of this form of POAG.
[0006] Normotensive glaucoma is a chronic progressive optic
neuropathy resulting in typical optic nerve head changes, retinal
nerve fibers layer defects, and characteristic visual field
defects. In addition, the chamber angle is open and IOP values
within statistical normal limits (lower than 22 mmHg) (Lee et al.
1998; for review, see Hoyng and Kitazawa 2002).
[0007] There is evidence that treatment of normotensive glaucoma by
lowering IOP can slow the glaucomatous process. A reduction of at
least 30% in IOP is needed to induce a favorable alteration in this
disease.
[0008] Apart from both these main kinds of glaucoma other
pathologies can lead to an elevation of IOP, namely secondary
glaucoma including post-uveitic glaucoma and steroid-induced
glaucoma.
[0009] Prior art treatment of glaucoma consists in lowering the
intraocular pressure by administering drugs which either reduce the
production of aqueous humor within the eye or increase the fluid
drainage, such as beta-blockers, .alpha.-agonists, cholinergic
agents, carbonic anhydrase inhibitors, or prostaglandin
analogs.
[0010] Several side effects are associated with the drugs
conventionally used to treat glaucoma.
[0011] Topical beta-blockers show serious pulmonary side effects,
depression, fatigue, confusion, impotence, hair loss, heart failure
and bradycardia.
[0012] Topical .alpha.-agonists have a fairly high incidence of
allergic or toxic reactions; topical cholinergic agents (miotics)
can cause visual side effects.
[0013] The side effects associated with oral carbonic anhydrase
inhibitors include fatigue, anorexia, depression, paresthesias and
serum electrolyte abnormalities (The Merck Manual of Diagnosis and
Therapy, Seventeenth Edition, M. H. Beers and R. Berkow Editors,
Sec. 8, Ch. 100).
[0014] Finally, the topical prostaglandin analogs (bimatoprost,
latanoprost, travoprost, tafluprost and unoprostone) used in the
treatment of glaucoma can produce ocular side effects, such as
increased pigmentation of the iris, ocular irritation, conjunctival
hyperaemia, iritis, uveitis and macular oedema (Martindale,
Thirty-third edition, p. 1445).
[0015] Diseases of the macula, such as age-related macular
degeneration and diabetic macular edema, account for major causes
of blindness. The drugs currently used for treating diseases of the
macula are steroidal anti-inflammatory drugs such as triamcinolone
acetonide or fluocinolone. However intravitreal triamcinolone
injections are associated with many ocular complications including
elevation of intraocular pressure.
[0016] Elevated intraocular pressure is a common post-surgical
complications following ocular surgery such as pars plana
vitrectomy, vitreoretinal surgery, retinal detachment surgery,
panretinal photocoagulation.
[0017] It is known that in the eye nitric oxide (NO) has an
important role in certain physiological processes, e.g. regulation
of aqueous humor dynamics, vascular tone, retinal
neurotransmission, retinal ganglion cell death by apoptosis,
phototransduction and ocular immunological responses, on the other
hand, the overproduction of NO is involved in several diseases of
the eye.
[0018] U.S. Pat. No. 4,590,207 discloses ophthalmic solution
containing isosorbide mononitrate as an active ingredient for
treating and/or preventing intraocular hypertension and
glaucoma.
[0019] US patent application 2002/0168424 discloses the use of a
mixture of a nitric oxide (NO) donor such as nitrovasodilators like
minoxidil, nitroglycerin, L-arginine, isosorbide dinitrate, or
nitroprusside, and a cyclic guanosine 3',5'-monophosphate (cGMP)
specific phosphodiesterase type 5 (PDE5) inhibitor such as
sildenafil citrate for treating glaucoma or ocular hypertension.
The disclosed combinations promote systemic vascular relaxation,
enhanced blood flow to the optic nerve, dilation of the trabecular
meshwork, the Schlemm's canal and uveoscleral outflow channel
tissues, enhanced aqueous humor drainage and thus lowered
intraocular pressure (TOP) in mammalian eye.
[0020] Organic nitrates have been used for over a century in the
treatment of cardiac diseases however, it is known that the
classical organic nitrates used in therapy, such as glycerol
trinitrate, isosorbide dinitrate or isosorbide 5-mononitrate,
undergo tolerance and lose their activity upon repeated
administration. Nitrate tolerance develops despite an elevation in
the drug plasma concentration reflecting a decrease in vascular
sensitivity to previously therapeutic levels. This can be prevented
or reduced by inclusion of a nitrate free period in the dosing
schedule.
[0021] UK patent application no. GB 2 349 385 A discloses
antioxidant nitrate or nitrite ester for use as vasodilator agents
in the treatment of pathological conditions associated with
endothelial dysfunction, in particular heart diseases.
[0022] The disclosed compounds contain a superoxide scavenger
moiety and a nitrate or nitrite group and the two parts are stable
linked in order to reduce the degradation of the molecules under
physiological conditions. The stable link increases the activity of
the anti-oxidant scavenger that can avert reactive oxygen
species-mediated NO consumption of further production of
deleterious species.
[0023] Therefore, the technical problem underlying the present
invention is to provide effective therapeutic agents for the use in
the treatment and/or prophylaxis of hypertensive glaucoma,
normotensive glaucoma secondary glaucoma and ocular
hypertension.
[0024] Surprisingly, it has now been found that the nitric oxide
donors of the present invention lower intraocular pressure and
develop significant inferior tolerance than that of nitric oxide
donors described in the art.
[0025] It has also been surprisingly found that the nitric oxide
donors of the present invention have additional beneficial
anti-inflammatory and antioxidant properties that work
synergistically with the delivery of nitric oxide to promote
regulation of aqueous humor outflow through the trabecular
meshwork, cells repairing and protection.
[0026] The present invention relates to compounds of formula (I) or
stereoisomers thereof.
[0027] The present invention relates to compounds of formula
(I)
##STR00001##
[0028] or stereoisomers thereof, wherein:
[0029] R.sub.1 is selected from H, methyl, methoxy;
[0030] R.sub.2 is H or methyl;
[0031] R.sub.3 is selected from H, methyl, methoxy;
[0032] or R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0033] R.sub.4 and R.sub.5 are methyl and n is 1, or
[0034] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0035] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0036] p is 0 or 1;
[0037] R.sub.6 is H or methyl.
[0038] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0039] R.sub.1 is selected from H, methyl, methoxy;
[0040] R.sub.2 is methyl;
[0041] R.sub.3 is selected from H, methyl, methoxy;
[0042] or R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0043] R.sub.4 and R.sub.5 are methyl and n is 1,
[0044] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0045] p is 0 or 1;
[0046] R.sub.6 is H or methyl.
[0047] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0048] R.sub.1 is selected from H, methyl, methoxy;
[0049] R.sub.2 is methyl;
[0050] R.sub.3 is selected from H, methyl, methoxy;
[0051] or R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0052] R.sub.4 and R.sub.5 are methyl and n is 1,
[0053] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0054] p is 0 and R.sub.6 is H.
[0055] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0056] R.sub.1 is selected from H, methyl, methoxy;
[0057] R.sub.2 is methyl;
[0058] R.sub.3 is selected from H, methyl, methoxy;
[0059] or R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0060] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0061] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0062] p is 0 or 1;
[0063] R.sub.6 is H or methyl.
[0064] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0065] R.sub.1 is selected from H, methyl, methoxy;
[0066] R.sub.2 is methyl;
[0067] R.sub.3 is selected from H, methyl, methoxy; [0068] or
R.sub.1 and R.sub.3 together form --CH.dbd.CH--CH.dbd.CH--;
[0069] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0070] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0071] p is 0 and R.sub.6 is H.
[0072] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0073] R.sub.1 is selected from H, methyl, methoxy;
[0074] R.sub.2 is methyl;
[0075] R.sub.3 is selected from H, methyl, methoxy; [0076] or
R.sub.1 and R.sub.3 together form --CH.dbd.CH--CH.dbd.CH--;
[0077] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0078] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0079] p is 1 and R.sub.6 is H or methyl, preferably R.sub.6 is
H.
[0080] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0081] R.sub.1, R.sub.2 and R.sub.3 are methyl;
[0082] R.sub.4 and R.sub.5 are methyl and n is 1;
[0083] m is an integer from 1 to 6, most preferably 4 or 6;
[0084] p is 0 or 1;
[0085] R.sub.6 is H or methyl.
[0086] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0087] R.sub.1, R.sub.2 and R.sub.3 are methyl;
[0088] R.sub.4 and R.sub.5 are methyl and n is 1; [0089] m is an
integer from 1 to 6; [0090] p is 0 and R.sub.6 is H.
[0091] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0092] R.sub.1, R.sub.2, R.sub.3, are methyl;
[0093] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0094] m is an integer from 1 to 6, most preferably 4 or 6;
[0095] p is 0 or 1;
[0096] R.sub.6 is H or methyl.
[0097] Another embodiment of the invention provides a compound of
formula (I) or stereoisomers thereof, wherein:
[0098] R.sub.1, R.sub.2, R.sub.3, are methyl;
[0099] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0100] m is an integer from 1 to 6, most preferably 4 or 6;
[0101] p is 0 and R.sub.6 is H.
[0102] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0103] R.sub.1 is methoxy;
[0104] R.sub.2 is methyl;
[0105] R.sub.3 is methoxy;
[0106] R.sub.4 and R.sub.5 are methyl and n is 1; [0107] m is an
integer from 1 to 10, preferably m is an integer from 1 to 6, most
preferably 4 or 6;
[0108] p is 0 or 1;
[0109] R.sub.6 is H or methyl.
[0110] Another embodiment of the invention provides a compound of
formula (I) as above defined
[0111] or stereoisomers thereof, wherein:
[0112] R.sub.1 is methoxy;
[0113] R.sub.2 is methyl;
[0114] R.sub.3 is methoxy;
[0115] R.sub.4 and R.sub.5 are methyl and n is 1; [0116] m is an
integer from 1 to 10, preferably m is an integer from 1 to 6, most
preferably 4 or 6; [0117] p is 0 and R.sub.6 is H.
[0118] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0119] R.sub.1 is methoxy;
[0120] R.sub.2 is methyl;
[0121] R.sub.3 is methoxy;
[0122] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0123] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0124] p is 0 or 1;
[0125] R.sub.6 is H or methyl.
[0126] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0127] R.sub.1 is methoxy;
[0128] R.sub.2 is methyl;
[0129] R.sub.3 is methoxy;
[0130] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0131] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0132] p is 0 and R.sub.6 is H.
[0133] Another embodiment of the invention provides a compound of
formula (I) or stereoisomers thereof, wherein:
[0134] R.sub.2 is methyl;
[0135] R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0136] R.sub.4 and R.sub.5 are methyl and n is 1;
[0137] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0138] p is 0 or 1;
[0139] R.sub.6 is H or methyl.
[0140] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0141] R.sub.2 is methyl;
[0142] R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0143] R.sub.4 and R.sub.5 are methyl and n is 1;
[0144] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0145] p is 0 and R.sub.6 is H.
[0146] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0147] R.sub.2 is methyl;
[0148] R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0149] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0150] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0151] p is 0 or 1;
[0152] R.sub.6 is H or methyl.
[0153] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0154] R.sub.2 is methyl;
[0155] R.sub.1 and R.sub.3 together form
--CH.dbd.CH--CH.dbd.CH--;
[0156] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0157] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0158] p is 0 and R.sub.6 is H.
[0159] Another embodiment of the invention provides a compound of
formula (I) as above defined
[0160] or stereoisomers thereof, wherein:
[0161] R.sub.1 is methyl;
[0162] R.sub.2 is methyl;
[0163] R.sub.3 is methoxy;
[0164] R.sub.4 and R.sub.5 are methyl and n is 1; [0165] m is an
integer from 1 to 10, preferably m is an integer from 1 to, most
preferably 4 or 6;
[0166] p is 0 or 1;
[0167] R.sub.6 is H or methyl.
[0168] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0169] R.sub.1 is methyl;
[0170] R.sub.2 is methyl;
[0171] R.sub.3 is methoxy;
[0172] R.sub.4 and R.sub.5 are methyl and n is 1;
[0173] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0174] p is 0 and R.sub.6 is H.
[0175] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0176] R.sub.1 is methyl;
[0177] R.sub.2 is methyl;
[0178] R.sub.3 is methoxy;
[0179] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0180] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0181] p is 0 or 1;
[0182] R.sub.6 is H or methyl.
[0183] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0184] R.sub.1 is methyl;
[0185] R.sub.2 is methyl;
[0186] R.sub.3 is methoxy;
[0187] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0188] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0189] p is 0 and R.sub.6 is H.
[0190] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0191] R.sub.1 is methoxy;
[0192] R.sub.2 is methyl;
[0193] R.sub.3 is methyl;
[0194] R.sub.4 and R.sub.5 are methyl and n is 1;
[0195] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0196] p is 0 or 1;
[0197] R.sub.6 is H or methyl.
[0198] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0199] R.sub.1 is methoxy;
[0200] R.sub.2 is methyl;
[0201] R.sub.3 is methyl;
[0202] R.sub.4 and R.sub.5 are methyl and n is 1;
[0203] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0204] p is 0 and R.sub.6 is H.
[0205] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0206] R.sub.1 is methoxy;
[0207] R.sub.2 is methyl;
[0208] R.sub.3 is methyl;
[0209] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0210] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0211] p is 0 or 1;
[0212] R.sub.6 is H or methyl.
[0213] Another embodiment of the invention provides a compound of
formula (I) as above defined or stereoisomers thereof, wherein:
[0214] R.sub.1 is methoxy;
[0215] R.sub.2 is methyl;
[0216] R.sub.3 is methyl;
[0217] R.sub.4 is H, R.sub.5 is selected from phenyl,
para-fluorophenyl, para-methoxyphenyl, para-isopropylphenyl,
para-trifluoromethylphenyl and para-methylphenyl and n is 2;
[0218] m is an integer from 1 to 10, preferably m is an integer
from 1 to 6, most preferably 4 or 6;
[0219] p is 0 and R.sub.6 is H.
[0220] Another embodiment of the invention provides a compound of
formula (I) selected from the group:
##STR00002## ##STR00003## ##STR00004## ##STR00005##
[0221] and stereoisomers thereof.
[0222] Another embodiment of the invention provides the use of the
compound of formula (I) for use in treating hypertensive glaucoma,
normotensive glaucoma, secondary glaucoma and ocular
hypertension.
[0223] The tests performed demonstrated that compounds of formula
(I) show an antioxidant activity comparable with that of well known
antioxidant compounds like ferulic and caffeic acid or
edaravone.
[0224] Moreover the compounds of the present invention
significantly attenuated the saline-induced IOP rise in an in vivo
model of transient ocular hypertension in rabbit.
[0225] Consequently, the compounds of the invention may be used as
drug for the prevention and/or treatment of ocular pathologies
where not only a deficit of NO but also oxidative stress play an
important role in their pathogenesis.
[0226] Another embodiment of the present invention relates to
compounds of formula (I) for the treatment and/or prophylaxis of
hypertensive glaucoma, normotensive glaucoma secondary glaucoma and
ocular hypertension.
[0227] Another embodiment of the present invention to compounds of
formula (I) for the treatment of high intraocular pressure
resulting from orbital edema, post-surgical complications,
intraocular inflammation, pupillary block or idiopathic causes.
[0228] Furthermore the present invention relates to compounds of
formula (I) for the use in the treatment and/or prophylaxis of age
related macular degeneration, diabetic retinopathy, retinal vein
occlusion, macular degeneration, inflammatory retinal disease,
uveitis.
[0229] The present inventions also relates to compositions
comprising a nitric oxide donor of formula (I) in combination with
one or more further active ingredients selected from the group
consisting of alpha adrenergic agonist, beta blocker, carbonic
anhydrase inhibitor, prostaglandin analogs, non-steroidal
anti-inflammatory drugs, steroidal anti-inflammatory drugs.
[0230] Examples of suitable alpha adrenergic agonists are
brimonidine, apraclonidine, clonidine.
[0231] Examples of suitable beta blockers are timolol, carteolol,
betaxolol, levobunolol.
[0232] Examples of suitable carbonic anhydrase inhibitors are
dorzolamide, acetazolamide, brinzolamide, dorzolamide,
dichlorphenamide, methazolamide.
[0233] Examples of suitable prostaglandin analogs are bimatoprost,
latanoprost, travoprost, unoprostone and tafluprost.
[0234] Examples of non-steroidal anti-inflammatory drugs are
bromfenac, flurbiprofen, naproxen, ketoprofen.
[0235] Examples of steroidal anti-inflammatory drugs are
dexamethsone, fluocinolone acetonide, triamcinolone acetonide,
budesonide, prednisolone.
[0236] Another embodiment of the present invention is a composition
above reported for use in the treatment and/or prophylaxis of
hypertensive glaucoma, normotensive glaucoma, secondary glaucoma
and ocular hypertension.
[0237] Another embodiment of the present invention is a composition
above reported for use in the treatment and/or prophylaxis of
secondary glaucomas, age related macular degeneration, diabetic
retinopathy, macular degeneration, inflammatory retinal disease,
uveitis.
[0238] Another embodiment of the present invention is a composition
above reported for use in the treatment of high intraocular
pressure resulting from orbital edema, post-surgical complications,
intraocular inflammation, pupillary block, or idiopathic
causes.
[0239] Another embodiment of the present invention provides
pharmaceutical formulation for topical, periocular or intraocular
administration comprising at least a nitric oxide donor of formula
(I) and at least an ophthalmically acceptable component and/or
ophthalmic ally acceptable vehicle.
[0240] Another embodiment of the present invention provides
pharmaceutical formulation for topical, periocular or intraocular
administration comprising at least a nitric oxide donor of formula
(I) one or more further active ingredients selected from the group
consisting of alpha adrenergic agonist, beta blocker, carbonic
anhydrase inhibitor, prostaglandin analogs, non-steroidal
anti-inflammatory drugs, steroidal anti-inflammatory drugs and at
least an ophthalmically acceptable component and/or ophthalmically
acceptable vehicle.
[0241] The preferred route of administration of the compounds and
compositions of the present invention is topical or intravitreal.
The compounds and compositions of the present invention can be
administered as solutions, suspensions, or emulsions (dispersions)
for topical use.
[0242] The compounds for use in the current invention can also be
administered via periocular administration, and may be formulated
in solutions or suspensions for periocular administration.
Formulations useful for periocular administration will generally be
periocular injection formulations or surgical irrigating solutions.
Periocular administration refers to administration to tissues near
the eye, such as administration to the tissues or spaces
surrounding the eyeball and within the orbit. Periocular
administration can take place by injection, deposit, or any other
mode of placement.
[0243] The compounds and the compositions of the present invention
compositions may be formulated in solutions or suspensions for
intraocular administration. Compositions useful for intraocular
administration will generally be intraocular injection compositions
or surgical irrigating solutions.
[0244] An "ophthalmically acceptable" component refers to a
component which will not cause any significant ocular damage or
ocular discomfort at the intended concentration and over the time
of intended use. Solubilizers and stabilizers should be
non-reactive. An "ophthalmically acceptable vehicle" refers to any
substance or combination of substances which are non-reactive with
the compounds and suitable for administration to a patient.
[0245] The nitric oxide donors of the present invention will
generally be contained in the topical, periocular, or intraocular
formulations contemplated herein in an amount of from about 0.001
to about 10.0% weight/volume. Preferred concentrations will range
from about 0.1 to about 5.0% w/v.
[0246] General Synthesis
[0247] The compounds of formula (I) wherein R.sub.1, R.sub.2,
R.sub.3, R.sub.6, m and p are as above defined, R.sub.4 and R.sub.5
are methyl n is 1 can be prepared:
[0248] by reacting compounds (Va) with compounds of formula (VI)
wherein R.sub.6, m and p are as above defined, in presence of
coupling reagents such as DCC, EDC, HBTU, HATU, and of catalytic
amount of DMAP or Sc(OTf).sub.3 in an aprotic/non polar solvent
such as THF, DMF or CH.sub.2Cl.sub.2 or at temperature ranging from
-80.degree. C. to 60.degree. C. as depicted in Scheme 1; or
[0249] by reacting compounds of formula (Vb), wherein Xa is an
activating group selected from N.sub.3, F, Cl, Br, or a group
depicted in Formulas ((Xaa) or (Xbb),
##STR00006##
[0250] preferably Cl or (Xaa), with compounds (VI) in presence of a
base such as DMAP, pyridine or triethylamine or K.sub.2CO.sub.3,
Cs.sub.2CO.sub.3 in an aprotic/non polar solvent such as THF, DMF
or CH.sub.2Cl.sub.2 or at temperature ranging from -80.degree. C.
to 60.degree. C. as depicted in Scheme 1:
##STR00007##
[0251] Compounds of formula (Vb) can be prepared by known method
from the corresponding compounds of formula (Va). Compounds of
formula (Va) can be generally prepared as depicted in Scheme 2
following the method described by Carpino et al., J. Org. Chem.,
1989, 54, 3303-3310.
##STR00008##
[0252] Hydroquinones of general formula (III) are reacted with
methanesulfonic acid and methyl 3-methylbut-2-enoate to obtain the
lactones (IV) as described in literature by Carpino et al., J. Org.
Chem., 1989, 54, 3303-3310.
[0253] Compounds of formula (Va) are prepared by reacting compounds
(IV) with an oxidant such as freshly crystallized NBS or PDC
according to conditions described by Borchardt et al., J. Am. Chem.
Soc., 1972, 94, 9175 and Carpino et al., J. Org. Chem., 1989, 54,
3303-3310.
[0254] Compounds of formula (III) are commercially available or can
be prepared by reduction of the corresponding quinones of formula
(II), using reducing reagents such as, for example NaBH.sub.4 in
methanol (Scheme 3).
[0255] Quinones of formula (II) are commercially available or can
be prepared by methods described in the literature.
##STR00009##
[0256] Compounds of formula (VI) wherein m, p and R.sub.6 are as
above defined, are known in the literature or can be synthesized
starting from the corresponding alcohols of formula (VIIa)
##STR00010##
[0257] wherein PG is a suitable hydroxyl protective group,
preferably an ester such as a benzoic ester, and m, p and R.sub.6
are as above defined by reaction with nitric acid and acetic
anhydride in a temperature range from -50.degree. C. to 20.degree.
C., or by reacting with triflic anhydride/tetraalkylammonium
nitrate salt in an aprotic polar/non polar solvent such as DMF, THF
or CH2Cl2 at temperature ranging from -80.degree. C. to 65.degree.
C. in the presence of a base as pyridine, lutidine,
2,6-di-tert-butyl-4-methylpyridine followed by the removal of the
protective group by known methods (see for example: T. W. Greene,
P. G. M. Wuts "Protective groups in organic Synthesis", 4th
edition, J. Wiley & Sons, New York, 2006).
[0258] Alternatively, the hydroxyl group of (VIIa) are first
converted to the corresponding mesyl or tosyl or triflate group and
then nitrated using known methods, as for example
tetraalkylammonium nitrate and sodium nitrate followed by the
removal of the protecting group by methods well known in the
art.
[0259] Alternatively compounds of formula (VI) wherein m and
R.sub.6 are as above defined, p is 0 can be synthesized by reacting
the corresponding halogen derivative (VIIb) wherein Q is H or PG
wherein PG is as previously defined and X is an halogen atom as Cl,
Br, I with a nitrating agent, for example, AgNO.sub.3 in
acetonitrile as known in the literature, followed by the removal of
the Q protecting group, when present, by methods well known in the
art.
##STR00011##
[0260] Compound of formula (VIIa) wherein m is as previously
defined, p is 1 and R.sub.6 is H or CH.sub.3 can be synthesized by
reacting the corresponding alkenyl-alcohol of formula (VIIIb) with
a dihydroxylating reagent such as ADmix .alpha. or ADmix.beta. or
KMnO.sub.4, OsO.sub.4 in a 1/1 mixture of protic/aprotic solvents
like tBuOH, H.sub.2O, optionally in the presence of an activator
like methanesulfonamide at temperature ranging from -20 to
30.degree. C., optionally followed by a chiral separation of the
diols (VIIa)
##STR00012##
[0261] Compounds of formula (VIIIb) are prepared from compounds
(VIIIa) by protecting the free hydroxyl group with a suitable PG
group already defined with known methods (see for example: T. W.
Greene, P. G. M. Wuts "Protective groups in organic Synthesis", 4th
edition, J. Wiley & Sons, New York, 2006).
[0262] Compounds (VIIa) are commercially available or can be
prepared from known compounds using known methods.
[0263] Alternatively compounds (VI) wherein m is as above defined,
p is 1 and R.sub.6 is H can be prepared by reacting compounds
(VIIIb) with I.sub.2 and AgNO.sub.3 in acetonitrile as described in
the literature (see Cena, C. et al in Bioorganic & Medicinal
Chemistry 2008, 16, 5199-5206.
[0264] Alternatively compounds (VI) wherein m is as above defined,
p is 1 and R.sub.6 is CH.sub.3 can be obtained from compounds
(VIIa) as depicted in Scheme 4, according the following steps:
##STR00013##
1) protecting the primary hydroxyl group of compounds (VIIa) 2)
protecting the secondary hydroxyl group to obtain compounds of
formula (X) wherein PG.sub.1 is the trityl group and PG.sub.2 is
TBDPS, TBDMS or TIPS. 3) removing the protecting group PG.sub.1 and
oxidizing compound (XI) to aldehyde with known methods to obtain
compounds (XII) 4) reacting compound (XII) with compound (XIII)
CH.sub.3-D-Z.sub.2 (XIII)
[0265] wherein D is Zn, Mg, or Cu, preferably Zn; Z is R or a
halogen, preferably Cl, in the presence of a chiral amino alcohol
catalyst such as (1S,2R)-(-)-(dibutylamino)-1-phenyl-1-propanol or
(1R,2S)-(+)-(dibutylamino)-1-phenyl-1-propanol or an achiral
catalyst in an aprotic/non polar solvent such as toluene, THF or
Et.sub.2O at temperature ranging from -80.degree. C. to 65.degree.
C.
5) removing the protecting group PG.sub.2 by methods well known in
the art to obtain compound (VI).
[0266] Compounds of formula (I) wherein R.sub.4 is H and R.sub.5 is
selected from phenyl, para-fluorophenyl, para-methoxyphenyl,
para-isopropylphenyl, para-trifluoromethylphenyl and
para-methylphenyl, n is 2 and R.sub.1, R.sub.2, R.sub.3, R.sub.6 m
and p are as above defined, can be prepared:
[0267] by reacting compounds of formula (XVIIIa) wherein R.sub.1,
R.sub.2, R.sub.3 are as above defined, R.sub.8 is H, F,
CH.sub.3O--, (CH.sub.3).sub.2CH--, CF.sub.3-- or CH.sub.3--, with
compounds of formula (VI) as above defined, in presence of a
coupling reagent such as DCC, EDC, HBTU, HATU, and of catalytic
amount of Sc(OTf).sub.3 or DMAP, as depicted in scheme 5;
[0268] by reacting compounds of formula (XVIIIb) wherein R.sub.1,
R.sub.2, R.sub.3, R.sub.8 and Xa are as above defined, with
compounds of formula (VI) in presence of a base such as DMAP
pyridine or triethylamine or K.sub.2CO.sub.3, Cs.sub.2CO.sub.3 in
an aprotic/non polar solvent such as THF, DMF or CH.sub.2Cl.sub.2
or at temperature ranging from -80.degree. C. to 60.degree. C. as
depicted in Scheme 5:
##STR00014##
[0269] Compounds of formula (XVIIIb) can be obtained using known
methods starting from the corresponding compounds of formula
(XVIIIa).
[0270] Compound of formula (XVIIIa) can be prepared by oxidation of
carboxylic acids of formula (XVII) wherein R.sub.1, R.sub.2,
R.sub.3 and R.sub.8 are as above described according to the
procedure disclosed by Jurd and Wong, Aust. J. Chem. 1980, 33, 137,
as depicted in Scheme 6.
[0271] Carboxylic acids of formula (XVII) can be prepared by
acid-catalyzed coupling reaction between hydroquinone (III) and the
commercially available .gamma.-lactone (XVI)
##STR00015##
EXAMPLE 1
Synthesis of 4-(nitrooxy)butyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 1)
##STR00016##
[0272] Step 1: Synthesis of
6-hydroxy-4,4,5,7,8-pentamethylchroman-2-one
##STR00017##
[0274] A synthetic procedure similar to the one described by
Carpino et al., J. Org. Chem., 1989, 54, 3303-3310 was used.
[0275] Methanesulfonic acid (20 mL) was heated at 70.degree. C. In
parallel, 2,3,5-trimethylbenzene-1,4-diol (2.0 g, 13.14 mmol) and
methyl 3-methylbut-2-enoate (1.94 mL, 13.14 mmol, 1 eq) were added
quickly and the reaction was heated for 2 h at this temperature.
The reaction was then poured in water and, after cooling, was
extracted with EtOAc (3.times.100 mL). The combined organic layers
were washed successively with water, saturated NaHCO.sub.3, water
and brine, dried (Na.sub.2SO.sub.4), filtered and evaporated. The
residue was crystallized from 30% CHCl.sub.3 in n-Hexane to give
the title compound as a pale grey solid (1.86 g, Yield: 60%).
Melting point: 185.degree. C.
[0276] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.63 (s, 1H), 2.54
(s, 2H), 2.36 (s, 3H), 2.22 (s, 3H), 2.18 (s, 3H), 1.45 (s,
6H).
Step 2: Synthesis of
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (Intermediate 2)
##STR00018##
[0278] The reaction was performed according to conditions described
by Borchardt et al., J. Am. Chem. Soc., 1972, 94, 9175.
[0279] A stirred solution of
6-hydroxy-4,4,5,7,8-pentamethylchroman-2-one (2.0 g, 0.853 mmol) in
10% aqueous acetonitrile (100 mL) was added with a solution of
freshly recrystallised NBS (1.6 g, 0.853 mmol, 1 eq) in
acetonitrile (20 mL). The reaction was stirred for 1 h and then
diluted with water (100 mL) and extracted with Et.sub.2O
(3.times.100 mL). The combined organic layers were washed with
water and brine, dried (Na.sub.2SO.sub.4), filtered and evaporated.
The residue was crystallized from Et.sub.2O/n-Hexane to give the
title compound as a yellow solid (1.64 g, Yield: 77%).
[0280] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 11.08-8.78 (m,
1H), 3.02 (s, 2H), 2.14 (s, 3H), 1.95 (s, 3H), 1.93 (s, 3H), 1.44
(s, 6H).
Step 3: Synthesis of 4-hydroxybutyl 4-nitrobenzoate
##STR00019##
[0282] A stirred solution of 1,4-butandiol (3.0 g, 33.29 mmol, 1.1
eq) and 4-nitrobenzoyl chloride (5.56 g, 29.96 mmol) in EtOAc (100
mL) cooled to 0.degree. C. was added dropwise with triethylamine
(4.6 mL, 33.3 mmol, 1.1 eq) and the reaction was stirred vigorously
for 6 h. The reaction was diluted with water and the organic layer
separated, washed with HCl 0.1 M, water and brine. The organic
phase was dried (Na.sub.2SO.sub.4), filtered and evaporated. The
residue was triturated in cold Et.sub.2O and the solid filtered
off. The filtrate was evaporated to give the title compound as a
viscous oil which solidified upon standing (2.86 g, Yield:
40%).
[0283] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.30 (d, J=8.8,
2H), 8.22 (d, J=8.8, 2H), 4.44 (t, J=6.5, 2H), 3.76 (t, J=6.3, 2H),
1.93 (dt, J=14.4, 6.7, 2H), 1.75 (dt, J=13.2, 6.4, 2H).
Step 4: Synthesis of 4-(nitrooxy)butyl 4-nitrobenzoate
##STR00020##
[0285] Concentrated nitric acid (1.9 mL, 45.15 mmol, 3 eq) was
added dropwise to acetic anhydride (20 mL) cooled to 0.degree. C.
Then solid 4-hydroxybutyl 4-nitrobenzoate was added and the
reaction was stirred at this temperature for 30 min then poured on
ice. After melting, the organic oil was separated from the aqueous
liquid and diluted with EtOAc. The organic layer was washed with
NaHCO3 (2.times.30 mL), water and brine, dried (Na2SO4), filtered
and evaporated. The residue was purified by flash chromatography
(Biotage System, SNAP Cartridge silica 100 g, eluent:
n-hexane/ethyl acetate 85/15 to n-hexane/ethyl acetate 75/25 during
8 CV) affording the title compound as a yellow oil (3.73 g, Yield:
87%).
[0286] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.34-8.29 (m, 2H),
8.24-8.19 (m, 2H), 4.56 (t, J=5.9, 2H), 4.44 (t, J=6.0, 2H),
1.99-1.90 (m, 4H).
Step 5: Synthesis of 4-hydroxybutyl nitrate
##STR00021##
[0288] A stirred solution of 4-(nitrooxy)butyl 4-nitrobenzoate
(2.13 g, 7.49 mmol) in a 3/1 THF/EtOH mixture (40 mL) cooled to
0.degree. C. was added with NaOH 1M (7.5 mL, 1 eq). The reaction
was stirred at this temperature for 3 h then diluted with EtOAc and
water. The organic layer was separated, washed with water and
brine, dried (Na.sub.2SO.sub.4), filtered and evaporated. The
residue was purified flash chromatography (Biotage System, SNAP
Cartridge silica 100 g, eluent: n-hexane/ethyl acetate 85/15 to
n-hexane/ethyl acetate 75/25 during 8 CV) affording the title
compound as a colourless oil (0.48 g, Yield: 49%).
[0289] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.52 (t, J=6.5,
2H), 3.72 (t, J=6.2, 2H), 1.87 (dt, J=14.2, 6.5, 2H), 1.75-1.63 (m,
1H).
Step 6: Synthesis of 4-(nitrooxy)butyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 1)
[0290] A stirred solution of 4-hydroxybutyl nitrate (prepared in
Step 5) (2.0 g, 14.8 mmol) and
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (prepared in Step 2) (3.70 g, 14.8 mmol) in dry
CH.sub.2Cl.sub.2 cooled to 0.degree. C. was added with EDC (3.12 g,
16.28 mmol, 1.1 eq) and a catalytic amount of DMAP (0.05 g). The
reaction was stirred for 5 h at this temperature and then washed
with water, HCl 1M, water and brine, dried (Na.sub.2SO.sub.4),
filtered and evaporated. The residue was purified by flash
chromatography (Biotage System, 2 SNAP Cartridge silica 340 g,
eluent: n-hexane/ethyl acetate 85/15 to n-hexane/ethyl acetate
70/30 during 8 CV) affording the title compound as a yellow oil
(5.02 g, Yield: 92%).
[0291] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.45 (t, J=6.2,
2H), 4.01 (t, J=6.1, 2H), 2.98 (s, 2H), 2.14 (s, 3H), 1.94 (s, 6H),
1.82-1.62 (m, 4H), 1.42 (s, 6H).
EXAMPLE 2
Synthesis of 6-(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 2)
##STR00022##
[0293] Step 1: Synthesis of 6-Nitrooxy-hexan-1-ol
##STR00023##
[0294] A solution of 6-bromohexan-1-ol (2.2 mL, 16.6 mmol) in
CH.sub.3CN (100 mL) was added with silver nitrate (5.95 g, 35 mmol,
2 eq). The reaction was stirred at room temperature for 3 days. The
reaction was quenched by addition of a solution of brine. After 15
min of stirring, the solution was filtered, extracted with ethyl
acetate, washed with H.sub.2O, brine, dried over sodium sulfate,
filtered and evaporated. The residue was purified by column
chromatography (Biotage System, SNAP Cartridge silica 100 g,
eluent: n-hexane/ethyl acetate 80/20 to n-hexane/ethyl acetate
50/50 during 12 CV) to give the desired product as a colorless oil
(2.34 g, Yield: 86%).
[0295] .sup.1H NMR (300 MHz, CDCl.sub.3) 4.47 (t, J=6.6 Hz, 2H),
3.68 (t, J=6.1 Hz, 2H), 1.77 (m, 2H), 1.62 (m, 2H), 1.48 (m, 4H),
1.27 (s, 1H).
Step 2: Synthesis of 6-(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
[0296] A stirred solution of 6-hydroxyhexyl nitrate (164 mg, 1.0
mmol) and
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (prepared in Example 1, Step 2) (250 mg, 1.0 mmol) in dry
CH2C12 cooled to 0.degree. C. was added with EDC (202 mg, 1.1 mmol,
1.1 eq) and a catalytic amount of DMAP (0.02 g). The reaction was
stirred for 16 h from 0.degree. C. to rt. The reaction was washed
with water, HCl 1M, water and brine, dried (Na.sub.2SO.sub.4),
filtered and evaporated. The residue was purified by flash
chromatography (Biotage System, SNAP Cartridge silica 100 g,
eluent: n-hexane/ethyl acetate 85/15 to n-hexane/ethyl acetate
70/30 during 8 CV) affording the title compound as a yellow oil
(286 mg, Yield: 72%).
[0297] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.44 (t, J=6.6,
2H), 3.97 (t, J=6.6, 2H), 2.97 (s, 2H), 2.12 (s, 3H), 1.94 (d,
J=10.4, 6H), 1.77-1.65 (m, 2H), 1.63-1.50 (m, 2H), 1.47-1.41 (m,
6H), 1.41-1.30 (m, 4H).
EXAMPLE 3
Synthesis of 6-(nitrooxy)hexyl
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 3)
##STR00024##
[0298] Step 1: Synthesis of
4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-4-phenylbutanoic acid
##STR00025##
[0300] The reaction was performed according to conditions described
by Mitsuru et al., J. Med. Chem. Soc., 1989, 32, 2214-2221.
[0301] Boron trifluoride etherate (0.25 ml; 1.99 mmol) was added
dropwise to a mixture of trimethylhydroquinone (1.0 g; 6.57 mmol)
and .gamma.-phenyl-.gamma.-butyrolactone (1.1 g; 6.57 mmol) in
toluene (70 ml) at 60.degree. C. during 10 minutes. The mixture was
stirred for further 2 hours and then the solvent was evaporated
under reduced pressure. The residue was purified by flash
chromatography (Biotage system, SNAP Cartridge silica 100 g, EtOAc
in n-hexane from 9% to 60% in 10 CV) affording the title compound
(0.74 g; Yield: 36%) as an orange solid.
[0302] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.39-7.07 (m, 5H),
4.72-4.25 (m, 3H), 2.74-2.25 (m, 4H), 2.25 (s, 3H), 2.08 (s, 3H),
1.98 (m, 2H).
Step 2: Synthesis of
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid
##STR00026##
[0304] To a solution of
4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-4-phenylbutanoic acid (0.74
g; 2.33 mmol) in CH.sub.3CN:H.sub.2O 1:1 (50 ml), Ammonium cerium
nitrate (3.3 g; 5.87 mmol) was added. The mixture was stirred 3
hours at room temperature then was poured into H.sub.2O (30 ml).
Et.sub.2O (20 ml) was added, the two phases were separated and the
organic layer was extracted with Et.sub.2O (2.times.20 ml). The
combined organic layers were washed with brine, dried on
Na.sub.2SO.sub.4 and concentrated affording 560 mg of the title
compound without any further purification.
[0305] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.40-7.06 (m, 5H),
4.35 (t, J=7.6, 1H), 2.77-2.25 (m, 4H), 2.15-2.03 (m, 3H), 1.97 (m,
6H).
Step 3: Synthesis of 6-(nitrooxy)hexyl
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(compound (3))
[0306] To a solution of
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (0.29 g; 0.92 mmol) and 6-Nitrooxy-hexan-1-ol (synthesised in
Example 2, step 1) (0.17 mg; 0.92 mmol) in CH.sub.2Cl.sub.2 (5 ml),
1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) (0.29 g; 1.38
mmol) and DMAP cat. were added. The solution was stirred 30 minutes
at 0.degree. C. and 4 hours at room temperature then washed with a
solution of NaH.sub.2PO.sub.4 5% (5 ml), H.sub.2O (5 ml) and brine.
The organic layer was dried over Na.sub.2SO.sub.4 and concentrated
under reduced pressure. The residue was purified by flash
chromatography (Biotage SP1 instrument, SNAP cartridge silica 50 g,
Hex/EtOAc 9:1, 10 CV) affording the title compound (0.35 g; Yield:
83%)
[0307] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.37-7.08 (m, 5H),
4.44 (t, 2H), 4.38-4.27 (m, 1H), 4.06 (t, 2H), 2.68-2.52 (m, 1H),
2.52-2.35 (m, 1H), 2.35-2.26 (m, 2H), 2.07 (s, 3H), 1.97 (m, 6H),
1.80-1.66 (m, 2H), 1.66-1.52 (m, 2H), 1.50-1.29 (m, 4H).
EXAMPLE 4
Synthesis of 4-(nitrooxy)butyl
3-methyl-3-(3-methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl)butanoate
(Compound 4)
##STR00027##
[0308] Step 1: Synthesis of
6-hydroxy-4,4,5-trimethyl-3,4-dihydro-2H-benzo[h]chromen-2-one
##STR00028##
[0310] Methanesulfonic acid (30 mL) was heated at 70.degree. C. In
parallel, 2-methylnaphthalene-1,4-diol (4.75 g, 25.0 mmol) and
methyl 3-methylbut-2-enoate (2.85 g, 25.0 mmol, 1 eq) were added
quickly and the reaction was heated for 2 h at this temperature.
The reaction was then poured in water and, after cooling, was
extracted with EtOAc (3.times.100 mL). The combined organic layers
were washed successively with water, saturated NaHCO.sub.3, water
and brine, dried (Na.sub.2SO.sub.4), filtered and evaporated. The
residue was purified flash chromatography (Biotage System, 2 SNAP
Cartridge silica 100 g, eluent: n-hexane/ethyl acetate 90/10 to
n-hexane/ethyl acetate 70/30 during 10 CV) affording the title
compound as a pale yellowish solid (2.26 g, Yield: 35%).
[0311] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.90 (d, J=8.3,
2H), 7.45 (d, J=8.0, 2H), 3.88-3.67 (m, 2H), 2.45 (s, 3H), 1.56 (s,
6H).
Step 2: Synthesis of
3-methyl-3-(3-methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl)butanoic
acid
##STR00029##
[0313] A stirred solution of
6-hydroxy-4,4,5-trimethyl-3,4-dihydro-2H-benzo[h]chromen-2-one (1.2
g, 4.44 mmol) in 10% aqueous acetonitrile (100 mL) was added with a
solution of freshly recrystallised NBS (0.8 g, 4.44 mmol, 1 eq) in
acetonitrile (20 mL). The reaction was stirred for 1 h and then
diluted with water (100 mL) and extracted with Et.sub.2O
(3.times.100 mL). The combined organic layers were washed with
water and brine, dried (Na.sub.2SO.sub.4), filtered and evaporated.
The residue was purified flash chromatography (Biotage System, SNAP
Cartridge silica 100 g, eluent: n-hexane/ethyl acetate 70/30 to
n-hexane/ethyl acetate 50/50 during 8 CV) affording the title
compound as a yellow oil (0.86 g, Yield: 68%).
[0314] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 12.11 (m, 1H),
8.06-7.99 (m, 1H), 7.87-7.78 (m, 1H), 7.70-7.58 (m, 2H), 3.02 (s,
2H), 2.14 (s, 3H), 1.44 (s, 6H).
Step 3: 4-(nitrooxy)butyl
3-methyl-3-(3-methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl)butanoate
(Compound 4)
[0315] A solution of 4-hydroxybutyl nitrate (synthesized in Example
1, steps 1, 2 and 3) (150 mg, 1.11 mmol) and
3-methyl-3-(3-methyl-1,4-dioxo-1,4-dihydronaphthalen-2-yl)butanoic
acid (303 mg, 1.11 mmol, 1 eq) in dry CH.sub.2Cl.sub.2 cooled to
0.degree. C. was added with EDC (234 mg, 1.22 mmol, 1.1 eq) and a
catalytic amount of DMAP. The reaction was stirred for 6 h at
0.degree. C. and then washed with water, HCl 0.1 M, water and
brine, dried (Na.sub.2SO.sub.4), filtered and evaporated. The
residue was purified flash chromatography (Biotage System, SNAP
Cartridge silica 100 g, eluent: n-hexane/ethyl acetate 80/20 to
n-hexane/ethyl acetate 70/30 during 8 CV) affording the title
compound as a yellow oil (268 mg, yield: 62%).
[0316] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.02 (dd, J=6.1,
2.9, 1H), 7.89-7.80 (m, 1H), 7.70-7.58 (m, 2H), 4.36 (t, J=6.3,
2H), 3.94 (t, J=6.2, 2H), 3.10 (s, 2H), 2.32 (s, 3H), 1.67 (dt,
J=10.8, 6.1, 2H), 1.65-1.45 (m, 14H).
EXAMPLE 5
Synthesis of 6-(nitrooxy)hexyl
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butan-
oate (Compound 5)
##STR00030##
[0317] Step 1: Synthesis of
4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-4-(4-fluorophenyl)butanoic
acid
##STR00031##
[0319] The reaction was performed according to conditions described
by Mitsuru et al., J. Med. Chem. Soc., 1989, 32, 2214-2221.
[0320] Boron trifluoride etherate (0.21 ml; 1.65 mmol) was added
dropwise to a mixture of trimethylhydroquinone (0.50 g; 3.30 mmol)
and .gamma.-(4-fluorophenyl)-.gamma.-butyrolactone (0.59 g; 3.30
mmol) in toluene (10 ml) at 60.degree. C. during 10 minutes. The
mixture was stirred for further 2 hours and then the solvent was
evaporated under reduced pressure. The residue was purified by
flash chromatography (Biotage system, SNAP Cartridge silica 50 g,
EtOAc in n-hexane from 9% to 60% in 10 CV) affording the title
compound (0.48 g; Yield: 43%) as an orange solid.
Step 2: Synthesis of
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)bu-
tanoic acid
##STR00032##
[0322] To a solution of
4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-4-(4-fluorophenyl)butanoic
acid (0.48 g; 1.44 mmol) in CH.sub.3CN:H.sub.2O 1:1 (40 ml),
ammonium cerium nitrate (2.04 g; 3.60 mmol) was added. The mixture
was stirred 3 hours at room temperature then was poured into
H.sub.2O (30 ml). Et.sub.2O (20 ml) was added, the two phases were
separated and the organic layer was extracted with Et.sub.2O
(2.times.20 ml). The combined organic layers were washed with
brine, dried on Na.sub.2SO.sub.4 and concentrated affording 430 mg
of the title compound without any further purification.
[0323] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.32-7.19 (m, 3H),
6.97 (m, 2H), 4.29 (t, J=7.6, 1H), 2.70-2.25 (m, 4H), 2.10 (s, 3H),
2.03-1.89 (m, 6H).
Step 3: 6-(nitrooxy)hexyl
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butan-
oate (Compound 5)
[0324] To a solution of
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)bu-
tanoic acid (0.22 g; 0.66 mmol) and 6-Nitrooxy-hexan-1-ol
(synthesised in Example 2, step 1) (0.12 mg; 0.66 mmol) in
CH.sub.2Cl.sub.2 (5 ml),
1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) (0.19 g; 0.98
mmol) and DMAP cat. were added. The solution was stirred 30 minutes
at 0.degree. C. and 4 hours at room temperature then washed with a
solution of NaH.sub.2PO.sub.4 5% (5 ml), H.sub.20 (5 ml) and brine.
The organic layer was dried over Na.sub.2SO.sub.4 and concentrated
under reduced pressure. The residue was purified by flash
chromatography (Biotage SP1 instrument, SNAP cartridge silica 50 g,
Hex/EtOAc 9:1, 10 CV) affording the title compound (0.18 g; Yield:
58%).
[0325] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.36-7.17 (m, 3H),
7.05-6.88 (m, 2H), 4.44 (t, 2H), 4.28 (t, 1H), 4.06 (t, 2H),
2.67-2.33 (m, 2H), 2.33-2.22 (m, 2H), 2.11 (s, 3H), 2.00 (s, 3H),
1.95 (s, 3H), 1.80-1.55 (m, 4H), 1.49-1.30 (m, 4H).
EXAMPLE 6
Synthesis of 4-(nitrooxy)butyl
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 6)
##STR00033##
[0326] Step 1: Synthesis of 4-chlorobutyl 4-nitrobenzoate
##STR00034##
[0328] To a solution of 4-Chlorobutanol (1.09 g; 10.04 mmol) and
TEA (1.7 ml; 12.05 mmol) in CH.sub.2Cl.sub.2 (25 ml) cooled at
0.degree. C., 4-Nitrobenzoyl chloride (2.23 g; 12.05 mmol) was
added portionwise. The mixture was stirred 2 hours at room
temperature then was washed with NaH2PO4 (25 ml), H.sub.2O and
brine. The residue was purified by flash chromatography (Biotage
SP1 instrument, SNAP cartridge silica 100 g, n-Hexane/EtOAc 9:1, 10
CV) affording the title compound (2.48 g; Yield: 96%)
[0329] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.38-8.25 (m, 2H),
8.25-8.14 (m, 2H), 4.55-4.33 (m, 2H), 3.73-3.53 (m, 2H), 2.13-1.85
(m, 4H).
Step 2: Synthesis of 4-(nitrooxy)butyl 4-nitrobenzoate
##STR00035##
[0331] To a solution of 4-chlorobutyl 4-nitrobenzoate (2.48 g; 9.62
mmol) in CH.sub.3CN (40 ml), NaI (5.77 g, 38.30 mmol) was added.
The mixture was heated in a microwave apparatus (40 minutes;
120.degree. C.) then the salts were filtered off and the solvent
evaporated under reduced pressure. EtOAc (50 ml) was added and the
solution was washed with a solution of Na.sub.2S.sub.2O.sub.5 5%
(50 ml), H.sub.2O and brine. The organic layer was dried on
Na.sub.2SO.sub.4 and concentrated under reduced pressure. The
residue was dissolved in CH.sub.3CN (40 ml) and AgNO3 (1.97 g;
11.54 mmol) was added. The mixture was heated at the mw for 15
minutes at 120.degree. C. then the salts were filtered off and the
solvent evaporated under reduced pressure. EtOAc (30 ml) was added,
the precipitate was removed again by filtration and the solvent was
evaporated. This procedure was repeated three times then the
organic layer was washed with brine, dried over Na.sub.2SO.sub.4
and concentrated under reduced pressure. The residue was purified
by flash chromatography (Biotage SP1 instrument, SNAP cartridge
silica 100 g, EtOAc in n-hexane from 5% to 40% in 10 CV) affording
the title compound (2.50 g; Yield: 93%) as a clear oil.
Step 3: Synthesis of 4-hydroxybutyl nitrate
##STR00036##
[0333] To a solution of 4-(nitrooxy)butyl 4-nitrobenzoate (2.5 g;
8.76 mmol) in THF (30 ml) cooled at 0.degree. C., NaOH 2M (8.7 ml;
17.53 mmol) was added dropwise. The solution was stirred 4 hours at
room temperature then was diluted with NaHCO3 sutured solution (20
ml) and extracted with CH.sub.2CL.sub.2 (3.times.30 ml). The
combined organic layers were dried over Na.sub.2SO.sub.4 and
concentrated under reduced pressure. The residue was purified by
flash chromatography (Biotage SP1 instrument, SNAP cartridge silica
50 g, EtOAc in n-hexane from 10% to 100% in 10 CV) affording the
title compound (1.0 g; Yield: 85%).
[0334] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 4.50 (td, J=6.5,
2H), 3.70 (t, J=6.2, 2H), 1.95-1.76 (m, 2H), 1.76-1.59 (m, 2H).
Step 4: Synthesis of 4-(nitrooxy)butyl
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 6)
[0335] To a solution of
4-phenyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (synthesized in Example 3, steps 1 and 2) (0.27 g; 0.86 mmol)
and 4-hydroxybutyl nitrate (0.15 mg; 0.86 mmol) in CH.sub.2Cl.sub.2
(4 ml), 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) (0.25
g; 1.30 mmol) and DMAP cat. were added. The solution was stirred 30
minutes at 0.degree. C. and 4 hours at room temperature then washed
with a solution of NaH.sub.2PO.sub.4 5% (5 ml), H.sub.20 (5 ml) and
brine. The organic layer was dried over Na.sub.2SO.sub.4 and
concentrated under reduced pressure. The residue was purified by
flash chromatography (Biotage SP1 instrument, SNAP cartridge silica
50 g, Hex/EtOAc 9:1, 10 CV) affording the title compound (0.23 g;
Yield: 62%) as an orange oil.
[0336] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.38-7.11 (m, 5H),
4.47 (m, 2H), 4.34 (t, J=7.7, 1H), 4.09 (t, J=6.0, 2H), 2.73-2.52
(m, 1H), 2.52-2.23 (m, 3H), 2.07 (s, 3H), 1.97 (m, 6H), 1.89-1.65
(m, 4H).
EXAMPLE 7
Synthesis of 4-(nitrooxy)butyl
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butan-
oate (Compound 7)
##STR00037##
[0338] To a solution of
4-(4-fluorophenyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)bu-
tanoic acid (synthesized in Example 5, steps 1 and 2) (0.19 g; 0.57
mmol) and 4-hydroxybutyl nitrate (synthesized in Example 6, steps
1, 2 and 3) (0.10 mg; 0.57 mmol) in CH.sub.2Cl.sub.2 (4 ml),
1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) (0.16 g; 0.86
mmol) and DMAP cat. were added. The solution was stirred 30 minutes
at 0.degree. C. and 4 hours at room temperature then washed with a
solution of NaH.sub.2PO.sub.4 5% (5 ml), H.sub.2O (5 ml) and brine.
The organic layer was dried over Na.sub.2SO.sub.4 and concentrated
under reduced pressure. The residue was purified by flash
chromatography (Biotage SP1 instrument, SNAP cartridge silica 50 g,
n-Hexane/EtOAc 9:1, 10 CV) affording the title compound (0.15 g;
Yield: 59%) as an orange oil.
[0339] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.35-7.15 (m, 2H),
7.06-6.87 (m, 2H), 4.47 (m, 2H), 4.28 (t, J=7.7, 1H), 4.09 (t,
J=6.0, 2H), 2.68-2.22 (m, 4H), 2.08 (s, 3H), 1.97 (m, 6H),
1.86-1.65 (m, 4H).
EXAMPLE 8
Synthesis of (5S,6R)-5,6-bis(nitrooxy)heptyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
((5S,6R)-isomer of Compound 8)
##STR00038##
[0340] Step 1: Synthesis of hex-5-enyl 4-nitrobenzoate
##STR00039##
[0342] At 0.degree. C., a solution of 5-hexen-1-ol (19.4 mL; 161.54
mmol) in dichloromethane (513 mL), was added with p-nitrobenzoyl
chloride (35.97 g, 193.85 mmol) followed by a solution of
triethylamine (27.0 mL, 193.85 mmol) in dichloromethane (150 mL)
dropwise. The mixture was stirred at ambient temperature for 21
hours, then washed with water, 1M aqueous HCl, brine. The organic
layer was dried (Na.sub.2SO.sub.4) and the solvent removed under
reduced pressure. The residue was purified by flash chromatography
(Biotage System, two SNAP Cartridge silica 340 g, eluent:
n-hexane/ethyl acetate 90/10 to n-hexane/ethyl acetate 50/50 during
12 CV) to give the title compound as a yellow oil (40.00 g,
99%).
[0343] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.30 (dt, J=9.0,
3.0 Hz, 2H), 8.22 (dt, J=9.0, 3.0 Hz, 2H), 5.83 (1H, ddt, J=16.9,
10.2, 6.7 Hz), 4.95-5.11 (2H, m), 4.39 (2H, t, J=6.6 Hz), 2.15 (2H,
m), 1.84 (2H, m) 1.50-1.66 (2H, m).
Step 2: Synthesis of (5S)-5,6-dihydroxyhexyl 4-nitrobenzoate
##STR00040##
[0345] To a vigorously stirred solution of commercially available
"AD mix .alpha." (112.5 g) in 1:1 water/t-butanol (822 mL), at
0.degree. C., hex-5-enyl 4-nitrobenzoate was added (20.00 g, 80.23
mmol). The mixture was stirred vigorously at 4.degree. C. (cold
room) for 21 hours. The mixture was cooled to 0.degree. C. and
ethyl acetate (450 mL) was added, followed by slow portionwise
addition of sodium metabisulfite (33.1 g). The mixture was stirred
at 0.degree. C. for 30 minutes, then at ambient temperature for 1
hour. The organic phase was separated and the aqueous extracted
with ethyl acetate. The combined organic extracts were washed with
brine, dried (Na.sub.2SO.sub.4) and the solvent removed under
reduced pressure. Purification by filtration over a short pad of
silica gel, eluting with ethyl acetate, gave the title compound as
an off-white solid (21.90 g, 96%).
[0346] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.30 (dt, J=9.0,
2.0 Hz, 2H), 8.21 (dt, J=9.0, 2.0 Hz, 2H), 4.39 (t, J=6.6 Hz, 2H),
3.80-3.62 (2H, m), 3.47 (1H, m), 2.59 (bs, 1H), 2.42 (bs, 1H),
1.90-1.75 (2H, m), 1.73-1.45 (4H, m).
Step 3: Synthesis of (5S)-6-triphenylmethyloxy-5-hydroxyhexyl
4-nitrobenzoate
##STR00041##
[0348] A solution of (5S)-5,6-dihydroxyhexyl 4-nitrobenzoate (13.46
g, 47.53 mmol) in anhydrous N,N-dimethylformamide (123 mL), under
N.sub.2, was added with triphenylchloromethane (14.57 g, 52.28
mmol), followed by triethylamine (7.29 mL, 52.28 mmol) and
4-dimethylaminopyridine (581 mg, 4.75 mmol). The resulting solution
was stirred at ambient temperature for 23 hours. The mixture was
poured into water and extracted with diethyl ether (.times.3). The
combined organic extracts were washed with saturated aqueous
NH.sub.4Cl and water, then dried (Na.sub.2SO.sub.4) and the solvent
removed under reduced pressure. Purification by flash
chromatography, eluting with 20% ethyl acetate/hexane to 50% ethyl
acetate/n-hexane gave the title compound as pale yellow oil (20.90
g, 84%).
[0349] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.28 (d, J=8.8 Hz,
2H), 8.20 (d, J=8.8 Hz, 2H), 7.49-7.42 (m, 6H), 7.36-7.23 (m, 9H),
4.36 (t, J=6.5 Hz, 2H), 3.82 (dp, J=10.9, 3.1 Hz, 1H), 3.21 (dd,
J=9.3, 3.3 Hz, 1H), 3.07 (dd, J=9.2, 7.7 Hz, 1H), 2.36 (d, J=2.9
Hz, 1H), 1.86-1.72 (m, 2H), 1.56-1.38 (m, 4H).
Step 4: Synthesis of
(5S)-6-triphenylmethyloxy-5-tert-butyldiphenylsilyloxyhexyl
4-nitrobenzoate
##STR00042##
[0351] A solution of (5S)-6-triphenylmethyloxy-5-hydroxyhexyl
4-nitrobenzoate (7.10 g, 13.51 mmol) in anhydrous
N,N-dimethylformamide (65 mL), under N.sub.2, was added with
imidazole (1.84 g, 27.02 mmol) and the solution cooled to 0.degree.
C. tert-Butyldiphenylsilyl chloride (7.03 mL, 27.02 mmol) was added
and the solution stirred at 0.degree. C. for 10 minutes, then at
ambient temperature for 15 hours. The mixture was poured into water
and extracted with diethyl ether. The combined organics were dried
(Na.sub.2SO.sub.4) and the solvent removed under reduced pressure.
Purification by flash chromatography, eluting with 5% ethyl
acetate/n-hexane gave the title compound as off-white foam (5.29 g,
51%).
[0352] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.28-8.20 (m, 2H),
8.19-8.09 (m, 2H), 7.67-7.53 (m, 4H), 7.48-7.11 (m, 21H), 4.22 (t,
J=6.4 Hz, 2H), 3.97-3.87 (m, 1H), 3.15 (dd, J=9.3, 4.8 Hz, 1H),
3.03 (dd, J=9.2, 6.4 Hz, 1H), 1.78-1.44 (m, 4H), 1.27 (m, 2H), 1.02
(s, 9H).
Step 5: Synthesis of (5S)-5-tert-butyldiphenyloxy-6-hydroxyhexyl
4-nitrobenzoate
##STR00043##
[0354] A solution of (5S)-6-triphenylmethyloxy-5-tert-butyldiphenyl
silyloxyhexyl-4-nitrobenzoate (4.06 g, 5.32 mmol) in
dichloromethane (15 mL) was added with methanol (157 mL) and
p-toluenesulfonic acid monohydrate (202 mg, 1.06 mmol). The
solution was stirred at ambient temperature for 17 hours. The
solvent was removed under reduced pressure and the residue
dissolved in ethyl acetate and washed with saturated aqueous
NaHCO.sub.3, water, then brine. The organic layer was dried
(Na.sub.2SO.sub.4) and the solvent removed under reduced pressure.
Purification by flash chromatography (Biotage System, SNAP
Cartridge silica 340 g, eluent: n-hexane/ethyl acetate 90/10 to
n-hexane/ethyl acetate 70/30 during 12 CV) gave the title compound
as a pale yellow oil (1.33 g, 48%).
[0355] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.32-8.26 (m, 2H),
8.20-8.15 (m, 2H), 7.73-7.66 (m, 5H), 7.48-7.35 (m, 5H), 4.25 (t,
J=6.5 Hz, 2H), 3.83 (dt, J=10.3, 5.3 Hz, 1H), 3.52 (ddd, J=11.4,
5.9, 3.7 Hz, 1H), 3.58 (ddd, J=11.4, 4.8, 3.1 Hz, 1H), 1.79 (bs,
1H), 1.70-1.46 (m, 4H), 1.36 (dd, J=15.0, 7.4 Hz, 2H), 1.09 (s,
9H).
Step 6: Synthesis of (5S)-5-tert-butyldiphenylsilyloxy-6-oxo hexyl
4-nitrobenzoate
##STR00044##
[0357] A 0.4 M solution of
(5S)-5-tert-butyldiphenyloxy-6-hydroxyhexyl 4-nitrobenzoate (9.29
g, 17.81 mmol) in dichloromethane (44.5 mL) was added with
silica-supported TEMPO (307 mg; 0.178 mmol), followed by a 0.5 M
solution aqueous KBr (3.53 mL). The mixture was cooled to 0.degree.
C. and stirred vigorously. A 0.37 M solution of NaOCl (10-15%
active CO (13.73 mL) in water (46.30 mL) was added and the mixture
buffered with solid NaHCO.sub.3. The mixture was stirred vigorously
at 0.degree. C. for 3.5 hours. The solids were removed by
filtration and washed well with dichloromethane and water. The
organic layer was separated and the aqueous extracted with
dichloromethane. The combined organics were dried
(Na.sub.2SO.sub.4) and the solvent removed under reduced pressure
to give the title compound as crude pale yellow oil (9.09 g, 98%)
for use directly without further purification.
[0358] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 9.64 (d, J=1.4 Hz,
1H), 8.30 (dt, J=9.0, 2.0 Hz, 2H), 8.19 (dt, J=9.0, 2.0 Hz, 2H),
7.75-7.60 (m, 4H), 7.55-7.35 (m, 6H), 4.30 (t, J=6.4 Hz, 2H), 4.09
(td, J=5.6, 1.4 Hz, 1H), 1.90-1.35 (m, 6H), 1.12 (9H, s).
Step 7: Synthesis of (5S,6R)-6-hydroxy-5-terbutyldiphenyl
silyloxyheptyl 4-nitrobenzoate and
(5S,6S)-6-hydroxy-5-terbutyldiphenylsilyloxyheptyl
4-nitrobenzoate
##STR00045##
[0360] A 250 mL schlenk flask (dried and flushed with N.sub.2) was
added with (1R,2S)-(+)-(dibutylamino)-1-phenyl-1-propanol (3.28 g,
12.45 mmol, 1 eq) followed by a 2 M solution of dimethylzinc in
toluene (37.35 mL, 74.7 mmol, 6 eq). The resulting yellow solution
was cooled to 0.degree. C. and a solution of
(5S)-5-tert-butyldiphenylsilyloxy-6-oxohexyl 4-nitrobenzoate (6.47
g, 12.45 mmol) in anhydrous toluene (40 mL) was added slowly. The
solution was stirred at 0.degree. C. for 10 minutes then allowed to
warm to ambient temperature and stirred for 18 hours. The solution
was cooled to 0.degree. C. and slowly quenched by addition of
saturated aqueous NH.sub.4Cl (75 mL). The mixture was allowed to
warm to ambient temperature and extracted with ethyl acetate. The
combined organics were dried (Na.sub.2SO.sub.4) and the solvent
removed under reduced pressure. Purification by flash
chromatography, eluting with 15% ethyl acetate/n-hexane to 25%
ethyl acetate/n-hexane gave the title compound, a yellow oil (4.31
g, 65%), as an inseparable mixture of the diastereoisomers 5S,6R
(major) and 5S,6S (minor).
[0361] (5S,6R)-major diastereoisomer
[0362] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.29 (dt, J=9.0,
2.0 Hz, 2H). 8.16 (dt, J=9.0, 2.0 Hz, 2H), 7.75-7.65 (4H, m),
7.50-7.30 (6H, m), 4.20 (t, J=6.4 Hz, 2H), 3.83 (m, 1H), 3.72 (m,
1H), 2.09 (d, J=4.9 Hz, 1H), 1.65-1.20 (m, 6H), 1.12 (d, J=6.5 Hz,
3H), 1.09 (s, 9H).
[0363] (5S,6S)-minor diastereoisomer:
[0364] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.29 (dt, J=9.0,
2.0 Hz, 2H), 8.16 (dt, J=9.0, 2.0 Hz, 2H), 7.75-7.65 (m, 4H),
7.30-7.50 (m, 6H), 4.20 (t, J=6.4 Hz, 2H), 3.71 (1H, m), 3.60 (1H,
m), 2.21 (d, J=6.1 Hz, 1H), 1.65-1.20 (m, 6H), 1.16 (d, J=6.3 Hz,
3H), 1.09 (s, 9H).
Step 8: Synthesis of (5S,6R)-5,6-dihydroxyheptyl
4-nitrobenzoate
##STR00046##
[0366] A solution of (5S,6R)-6-hydroxy-5-terbutyldiphenyl
silyloxyheptyl 4-nitrobenzoate (805 mg, 1.50 mmol) in diethyl ether
(50 mL) was added with a 3% solution of HCl in methanol, dropwise
(made from addition of acetyl chloride (2.00 mL) to methanol (50
mL)). The solution was stirred at ambient temperature for 41 hours.
Amberlite IRA 400 (OH) resin was added and the mixture stirred for
1 hour, with further addition of the resin until the pH=7/8. The
resin was filtered off and washed with ethyl acetate, then
methanol. The solvent was removed under reduced pressure and the
residue partitioned between ethyl acetate and saturated aqueous
NaHCO.sub.3 and the aqueous extracted with ethyl acetate. The
combined organics were dried (Na.sub.2SO.sub.4) and the solvent
removed under reduced pressure. Purification by flash
chromatography, eluting with 10% ethyl acetate/hexane to 90% ethyl
acetate/n-hexane, gave the title compound, a pale yellow oil (189
mg, 42%), as a mixture of the diastereoisomers 5S,6R (major) and
5S,6S (minor). Diastereoisomeric excess (5S,6R)=56.4%.
[0367] The diastereoisomers were separated by preparative HPLC
(conditions: column Phenomenex Gemini phenyl-hexyl 100.times.21.2
mm/5 m
[0368] Mobile phase: A: water+0.1% Formic acid; B: methanol+0.1%
formic acid.
[0369] Flow rate: 25 mL/min.
[0370] Gradient profile: time 0 min: 45% A/55% B; 5.5 min: 40%
A/60% B; 5.6 min: 0% A/100% B; 7.6 min: 0% A/100% B; 7.7 min: 45%
A/55% B. Detector: .delta.: 254 nm) to give compound H as a white
solid (135 mg). Enantiomeric excess/diastereomeric
excess=72.1%.
[0371] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.32 (dt, J=9.0,
2.0 Hz, 2H), 8.23 (dt, J=9.0, 2.0 Hz, 2H), 4.42, (t, J=6.5 Hz, 2H),
3.84 (m, 1H), 3.66 (m, 1H), 1.42-2.0 (m, 8H), 1.19 (d, J=6.4 Hz,
3H).
[0372] Alternative Deprotection Procedure
[0373] A stirred solution of (5S,6R)-6-hydroxy-5-terbutyldiphenyl
silyloxyheptyl 4-nitrobenzoate (2.96 g, 5.52 mmol) in acetonitrile
(60 mL) was added at 0.degree. C. with
borontrifluoride-diethyletherate (3.5 mL, 5 eq) and the reaction
was stirred at RT for 6 h.
[0374] The reaction was cooled to 0.degree. C. before quenching
with a saturated solution of sodium bicarbonate. The reaction was
diluted with ethyl acetate (50 mL) and the organic layer was
separated, washed successively with water and brine (5 mL each),
dried (Na.sub.2SO.sub.4), filtered and the solvent removed under
reduced pressure. The residue was purified by flash chromatography
(Biotage System, 2.times.SNAP Cartridge silica 100 g, eluent:
gradient n-hexane/ethyl acetate 35/65 to n-hexane/ethyl acetate
30/70 during 7 CV) to give the title compound as a colourless oil
(1.47 g, 90%) as a mixture of the diastereoisomers 5S,6R (major)
and 5S,6S (minor).
[0375] The diastereoisomers were separated by preparative HPLC
(conditions: column Phenomenex Gemini phenyl-hexyl 100.times.21.2
mm/5 m to give the major diastereoisomer as a white solid (1.09 g,
66%).
Step 9: Synthesis of (5S,6R)-5,6-bis(nitrooxy)heptyl
4-nitrobenzoate
##STR00047##
[0377] A stirred solution of (5S,6R)-5,6-dihydroxyheptyl
4-nitrobenzoate (400 mg, 1.34 mmol), tetrabutylammonium nitrate
(863 mg, 2.82 mmol, 2.1 eq) and 2,6-di-tert-butyl-4-methylpyridine
(580 mg, 2.82 mmol, 2.1 eq) in dry CH.sub.2Cl.sub.2 cooled to
-78.degree. C. was added dropwise with triflic anhydride (0.778 g,
2.75 mmol, 2.05 eq) and the reaction was stirred for 1 h at
-78.degree. C. and left to turn back to rt. The reaction was then
quenched with water and the organic layer was separated, washed
with water and brine, dried on sodium sulfate, filtered and
evaporated. The residue was purified by flash chromatography
(Biotage SP4, SNAP 100 column, EtOAc in n-hexane from 20% to 30% in
10 CV) affording the title compound as an yellow oil (406 mg,
Yield: 77%).
[0378] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.32 (dt, J=9.0
2.0 Hz, 2H), 8.22 (dt, J=9.0, 2.0 Hz, 2H), 5.30 (m, 1H), 4.42 (td,
J=6.4 Hz, 1H), 1.95-1.55 (m, 6H), 1.43 (d, J=6.7 Hz, 3H).
Step 10: Synthesis of (1R,2S)-6-hydroxy-1-methyl-2-(nitrooxy)hexyl
nitrate
##STR00048##
[0380] A solution of (5S,6R)-5,6-bis(nitrooxy)heptyl
4-nitrobenzoate (163 mg, 0.42 mmol) in tetrahydrofuran (1.27 mL)
and ethanol (1.27 mL), was added with a 1 M aqueous NaOH solution
(546 .mu.L, 0.546 mmol). The resulting yellow solution was stirred
at ambient temperature for 1.5 hours. The solvent was concentrated
under reduced pressure and the aqueous residue partitioned between
ethyl acetate and saturated aqueous NaHCO.sub.3. The organic layer
was washed with saturated aqueous NaHCO.sub.3 and the aqueous
back-extracted with ethyl acetate. The combined organics were dried
(Na.sub.2SO.sub.4) and the solvent concentrated to a small volume
(2 mL). The product was carefully purified by flash chromatography
(Biotage System, SNAP Cartridge silica 100 g, eluent: gradient
n-hexane/ethyl acetate 75/25 to n-hexane/ethyl acetate 50/50 during
8 CV) to give the separation of the two diastereoisomers and the
title compound as a colourless oil (0.147 g, 90%).
[0381] An optimal separation could be obtained using a Thar
Investigator SFC system using the following conditions:
[0382] Column: CHIRALPACK IB 250.times.10 mm (5 .mu.m)
[0383] Cosolvent: n-Hexane/2-Propanol 1/1
[0384] Isocratic elution: CO.sub.2/co-solvent 90/10
[0385] Flow 10 ml/min T column: 40.degree. C. Injection volume: 80
.mu.l Detector wavelength: 210 nm
[0386] Run time: 8.5 min Cycle time: 3 min Injected amount: 14-16
mg
[0387] (Sample preparation: 800 mg of crude compound were
solubilized in 4 ml of MeOH) .sup.1H NMR (300 MHz, CDCl.sub.3)
.delta. 5.25-5.34 (m, 2H), 3.70 (t, J=5.9 Hz, 2H), 1.47-1.85 (m,
7H), 1.42 (d, J=6.8 Hz, 3H).
Step 11: Synthesis of (5S,6R)-5,6-bis(nitrooxy)heptyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(compound 8)
[0388] A stirred solution of
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (Prepared in Example 1, Step 2) (146 mg, 0.583 mmol, 1 eq) and
(1R,2S)-6-hydroxy-1-methyl-2-(nitrooxy)hexyl nitrate (140 mg, 0.583
mmol) in dry CH.sub.2Cl.sub.2 cooled to 0.degree. C. was added with
EDC (117 mg, 0.612 mmol, 1.05 eq) and a catalytic amount of DMAP.
The reaction was stirred at this temperature for 5 h and then
washed with water, HCl 0.1 M, water and brine. The organic solution
was dried (Na.sub.2SO.sub.4), filtered and evaporated. The residue
was purified by flash chromatography (Biotage SP4 system, SNAP
Cartridge silica 100 g, eluent: gradient n-hexane/ethyl acetate
80/20 to n-hexane/ethyl acetate 70/30 during 8 CV) to give the
title compound as a yellow oil (210 mg, 76%).
[0389] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 5.32-5.17 (m, 2H),
3.99 (t, J=6.2, 2H), 2.98 (s, 2H), 2.14 (s, 3H), 1.98-1.94 (m, 6H),
1.76-1.45 (m, 15H), 1.43 (s, 6H), 1.39 (d, J=6.7, 3H).
EXAMPLE 9
Synthesis of (4-(nitrooxy)butyl
4-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-4-phenylbutanoat-
e (Compound 9)
##STR00049##
[0390] Step 1: Synthesis of
4-(2,5-dihydroxy-3,4-dimethoxy-6-methylphenyl)-4-phenylbutanoic
acid
##STR00050##
[0392] The reaction was performed according to conditions described
by Mitsuru et al., J. Med. Chem. Soc., 1989, 32, 2214-2221.
[0393] Boron trifluoride etherate (0.23 ml; 1.59 mmol) was added
dropwise to a mixture of 2,3-dimethoxy-5-methylbenzene-1,4-diol
(1.00 g; 5.49 mmol) and .gamma.-phenyl-.gamma.-butyrolactone (0.89
g; 5.49 mmol) in Toluene (55 ml) at 60.degree. C. during 10
minutes. The mixture was stirred for further 3 hours and then the
solvent was evaporated under reduced pressure. The residue was
purified by flash chromatography (Biotage system, SNAP Cartridge
silica 100 g, EtOAc in n-hexane from 9% to 60% in 10 CV) affording
the title compound (0.80 g; Yield: 42%) a pale yellow solid.
[0394] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.44-7.10 (m, 5H),
5.42 (m, 2H), 4.49 (m, 1H), 3.99-3.81 (m, 6H), 2.77-2.47 (m, 2H),
2.47-2.29 (m, 2H), 2.10 (s, 3H).
Step 2: Synthesis of 4-(4,5-dimethoxy-2-methyl-3,6-dioxo
cyclohexa-1,4-dien-1-yl)-4-phenylbutanoic acid
##STR00051##
[0396] To a solution of
4-(2,5-dihydroxy-3,4-dimethoxy-6-methylphenyl)-4-phenylbutanoic
acid (0.40 g; 1.15 mmol) in CH.sub.3CN:H.sub.2O 1:1 (40 ml),
Ammonium cerium nitrate (1.63 g; 2.89 mmol) was added. The mixture
was stirred 3 hours at room temperature then was poured into
H.sub.2O (30 ml). Et.sub.2O (20 ml) was added, the two phases were
separated and the organic layer was extracted with Et.sub.2O
(2.times.20 ml). The combined organic layers were washed with
brine, dried on Na.sub.2SO.sub.4 and concentrated affording 400 mg
of the title compound without any further purification.
Step 3: Synthesis of (4-(nitrooxy)butyl
4-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-4-phenylbutanoat-
e (Compound 9)
[0397] To a solution of
4-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dien-1-yl)-4-phenylbutan-
oic acid (0.40 g; 0.57 mmol) and 4-hydroxybutyl nitrate
(synthesised in Example 6, steps 1, 2 and 3) (0.10 mg; 0.57 mmol)
in CH.sub.2Cl.sub.2 (4 ml),
1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) (0.16 g; 0.86
mmol) and DMAP cat. were added. The solution was stirred 30 minutes
at 0.degree. C. and 4 hours at room temperature then washed with a
solution of NaH.sub.2PO.sub.4 5% (5 ml), H.sub.2O (5 ml) and brine.
The organic layer was dried over Na.sub.2SO.sub.4 and concentrated
under reduced pressure. The residue was purified by flash
chromatography (Biotage SP1 instrument, SNAP cartridge silica 25 g,
Hex/EtOAc 8:2, 10 CV) affording the title compound (95 mg; Yield:
36%) as a red oil.
[0398] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 7.38-7.15 (m, 5H),
4.49 (m, 2H), 4.35 (t, J=7.7, 1H), 4.11 (t, J=6.0, 2H), 3.98 (s,
6H), 2.74-2.52 (m, 1H), 2.52-2.25 (m, 3H), 2.09 (s, 3H), 1.89-1.66
(m, 4H).
EXAMPLE 10
In Vitro Antioxidant Activity (TBARS Test)
[0399] The antioxidant properties of compound (1) (example 1), its
precursors
(3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid, described in Example 1 Step 2 (Intermediate 2) and reference
antioxidant compounds were assessed after NADPH-induced lipidic
peroxidation of membrane lipids in rat hepatic microsomes using the
detection of 2-thiobarbituric acid reactive substances (TBARS) by
visible spectroscopy.
[0400] Hepatic microsomal membranes from male Wistar rats (200-250
g) were prepared by differential centrifugation (8000 g, 20 min;
120000 g, 1 h) in a HEPES/sucrose buffer (10 mM, 250 mM, pH 7.4)
and stored at -80.degree. C. Incubation was performed at 37.degree.
C. in a Tris-HCl/KCl (100 mM/150 mM, pH 7.4) containing microsomal
membranes (2 mg prot/mL), sodium ascorbate (100 .mu.M), and DMSO
solutions of the tested compounds.
[0401] Lipid peroxidation was initiated by adding ADP-FeCl.sub.3
and NADPH (Method A) or 2.5 .mu.M FeSO.sub.4 (Method B) (as
described by Boschi D. et al., J. Med. Chem. 2006, 49:2886-2897).
Aliquots were taken from the incubation mixture at 5, 15, and 30
min and treated with trichloroacetic acid (TCA) 10% w/v.
[0402] Lipid peroxidation was assessed by spectrophotometric (543
nm) determination of the TBARS consisting mainly of malondialdehyde
(MDA). TBARS concentrations (expressed in nmol/mg protein) were
obtained by interpolation with a MDA standard curve. The
antioxidant activity of tested compounds was evaluated as the
percent inhibition of TBARS production with respect to control
samples, using the values obtained after 30 min of incubation.
IC.sub.50 values were calculated by nonlinear regression
analysis.
[0403] The results reported in Table 1, showed that compound (1)
proved to inhibit in a concentration-dependent manner the
generation of TBARS with a potency (IC.sub.50=28 PA) that is
comparable to well known antioxidant compounds as ferulic or
caffeic acids, edavarone or melatonin.
TABLE-US-00001 TABLE 1 In vitro Antioxidant activity (TBARS test)
Antioxidant activity IC50 .mu.M Compound (CL 95%) Method Compound
(1) 28 (25-31) A Intermediate 2 157 (79-309) A Ferulic acid 50.5
.+-. 0.4.sup.a B Caffeic acid 33 (32-34) B Edavarone 17
(15-18).sup.b B Melatonin 476 (442-512).sup.c B Results are
expressed as IC.sub.50 of inhibition of TBARS production after 30
min incubation at 37.degree. C. Method A: inhibition of rat hepatic
lipid peroxidation induced by ADP-FeCl.sub.3 and NADPH. Method B:
inhibition of rat hepatic lipid peroxidation induced by FeSO4 and
ascorbic acid .sup.atested at 1 mM concentration; .sup.bChegaev, K.
et al. J. Med. Chem. 2009, 52: 574-578: .sup.cChegaev, K. et al. J.
Pineal Res. 2007, 42: 371-385
EXAMPLE 11
Intraocular Pressure (IOP) Lowering Activity in Hypertonic
Saline-Induced IOP Increase in Rabbits
[0404] The Intraocular pressure (TOP) lowering activity of compound
(1) (Example 1) was assessed in an animal model of elevated
IOP.
[0405] Adults male New Zealand White rabbits weighting 1.8-2.0 Kg
were used in the experiments.
[0406] Animals were anesthetized using 20 mg/ml/kg of sodium
pentobarbital. The increase in IOP was induced by the injection of
0.1 ml of hypertonic saline solution (5%) into the vitreous
bilaterally (Krauss et al., 2011, Orihashi et al., 2005).
[0407] IOP was measured using a Tono-Pen XL prior to hypertonic
saline injection (basal) and at 30, 60, 90, 120, 240 and 360 min
thereafter. Vehicle (5% cremophor-EL; 0.3% DMSO; 0.2 mg/ml
Benzalkonium chloride (bac) in PBS pH 6.0,) or compound of the
invention were instilled as eye drops immediately after hypertonic
saline injection. Eyes were randomly assigned to different
treatment groups. Vehicle or compounds of the invention were
directly instilled into the conjunctiva pocket at the desired
doses. One drop of 0.2% oxybuprocaine hydrochloride (Novesine,
Sandoz) diluted 1:1 with saline was instilled in each eye
immediately before each set of pressure measurements.
[0408] Results are reported in Table 2 in which the ocular
hypotensive activity of compound (1) is expressed as mean average
of IOP measurements at 60 and 120 minutes following topical
administration.
TABLE-US-00002 TABLE 2 Intraocular pressure (IOP) lowering activity
in hypertonic saline- induced IOP increase in rabbits IOP (mmHg) 60
minutes 120 minutes Compound (1) 29 .+-. 7.8 18.9 .+-. 4.1 Vehicle
34.9 .+-. 4.3 25.6 .+-. 4.6
EXAMPLE 12
Synthesis of (S)-5,6-bis(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 15; (S)-isomer of compound (10))
##STR00052##
[0409] Step 1: synthesis of (5S)-5,6-bis(nitrooxy)hexyl
4-nitrobenzoate
[0410] To a stirred solution of fuming nitric acid (7.7 mL, 91.8
mmol, 10 eq) in dichloromethane (60 mL) at -78.degree. C., was
added sulfuric acid (4 mL) and after 5 mins of stirring, a solution
of (5S)-5,6-dihydroxyhexyl 4-nitrobenzoate (prepared in Example 8
Step 2) (5.2 g, 9.2 mmol) in dichloromethane (30 mL) was added and
the reaction stirred at this temperature for 30 min. The crude
mixture was then poured on ice and the organic layer extracted,
washed with water, brine, dried over sodium sulfate, evaporated to
give the title compound as pale yellow oil (6.8 g, 100%). The
residue obtained was used in the next step without further
purification.
[0411] 1H NMR (300 MHz, CDCl3) .delta. 8.32 (d, J=8.9 Hz, 2H),
8.26-8.15 (m, 2H), 5.39-5.25 (m, 1H), 4.78 (dd, J=12.9, 3.1 Hz,
1H), 4.52 (dd, J=12.9, 6.4 Hz, 1H), 4.46-4.35 (m, 2H), 1.97-1.77
(m, 4H), 1.77-1.49 (m, 2H).
Step 2: Synthesis of (2S)-6-hydroxyhexane-1,2-diyl dinitrate
[0412] To a stirred solution of (5S)-5,6-bis(nitrooxy)hexyl
4-nitrobenzoate (prepared in Step 1) (6.8 g, 18.2 mmol) in a 1/1
mixture of ethanol/THF (30 mL of each) at 0.degree. C., a 2M sodium
hydroxide solution (9.1 mL, 2 eq) was added and the reaction was
stirred for 2 h. The reaction was diluted with ethyl acetate and
water (100 mL of each) and extracted. The organic layer was
successively washed with water and brine, dried over sodium sulfate
and evaporated. The oily residue was purified by column
chromatography (SNAP 100, gradient system from 4/6 ethyl
acetate/n-hexane to 60/40 ethyl acetate/n-hexane) to give the title
compound as colorless oil (3.82 g, 93%).
[0413] 1H NMR (300 MHz, CDCl3) .delta. 5.32 (qd, J=6.7, 3.0 Hz,
1H), 4.77 (dd, J=12.9, 3.0 Hz, 1H), 4.49 (dd, J=12.9, 6.6 Hz, 1H),
3.68 (d, J=5.5 Hz, 2H), 1.89-1.71 (m, 2H), 1.70-1.48 (m, 5H), 1.46
(s, 1H).
Step 3: Synthesis of (S)-5,6-bis(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
[0414] To a stirred solution of
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (201 mg; 0.80 mmol) (prepared as described in Example 1, steps
1 and 2) and (25)-6-hydroxyhexane-1,2-diyl dinitrate (181 mg; 0.80
mmol) (prepared in Step 2) in DCM (5 ml) cooled to 0.degree. C.,
EDAC (137 mg; 0.89 mmol) and a catalytic amount of DMAP were added.
The reaction was stirred overnight at 0.degree. C. The crude was
then washed with water, HCl 1N, water and brine, dried and
evaporated under vacuum. The crude was purified by flash
chromatography [Cy/EtOAc: 0% to 20% (1CV), 20% to 40% (7CV), 40% to
60% (2CV)] affording 246 mg of the title compound (Yield: 67.1%) as
a yellow oil.
[0415] .sup.1H NMR (300 MHz, acetone) .delta. 5.49 (qd, J=6.6, 2.6
Hz, 1H), 5.01 (dd, J=13.0, 2.6 Hz, 1H), 4.73 (dd, J=13.0, 6.3 Hz,
1H), 4.00 (t, J=6.3 Hz, 2H), 2.95 (s, 2H), 2.13 (s, 3H), 1.94 (s,
J=6.3 Hz, 6H), 1.90-1.79 (m, 2H), 1.70-1.58 (m, 2H), 1.52 (dt,
J=8.0, 5.7 Hz, 2H), 1.43 (s, 6H). .alpha..sub.D.sup.20=+2.2 (0.44%
MeOH)
EXAMPLE 13
Synthesis of (R)-5,6-bis(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
(Compound 16; (R)-isomer of compound 10)
##STR00053##
[0416] Step 1: Synthesis of (5R)-5,6-dihydroxyhexyl
4-nitrobenzoate
[0417] To a vigorously stirred solution of commercially available
"AD mix .beta." (112.5 g) in 1:1 water/t-butanol (822 mL), at
0.degree. C., hex-5-enyl 4-nitrobenzoate (prepared in Example 8,
Step 1) was added (20.00 g, 80.23 mmol). The mixture was stirred
vigorously at 4.degree. C. (cold room) for 21 hours. The mixture
was cooled to 0.degree. C. and ethyl acetate (450 mL) was added,
followed by slow portionwise addition of sodium metabisulfite (33.1
g). The mixture was stirred at 0.degree. C. for 30 minutes, then at
ambient temperature for 1 hour. The organic phase was separated and
the aqueous extracted with ethyl acetate. The combined organic
extracts were washed with brine, dried (Na2SO4) and the solvent
removed under reduced pressure. Purification by filtration over a
short pad of silica gel, eluting with ethyl acetate, gave the title
compound as an off-white solid (20.5 g, 90.2%).
[0418] 1H NMR (300 MHz, CDCl3) .delta. 8.30 (dt, J=9.0, 2.0 Hz,
2H), 8.21 (dt, J=9.0, 2.0 Hz, 2H), 4.39 (t, J=6.6 Hz, 2H),
3.80-3.62 (2H, m), 3.47 (1H, m), 2.59 (bs, 1H), 2.42 (bs, 1H),
1.90-1.75 (2H, m), 1.73-1.45 (4H, m).
Step 2: synthesis of (5R)-5,6-bis(nitrooxy)hexyl
4-nitrobenzoate
[0419] To a stirred solution of fuming nitric acid (7.7 mL, 91.8
mmol, 10 eq) in dichloromethane (60 mL) at -78.degree. C., was
added sulfuric acid (4 mL) and after 5 mins of stirring, a solution
of (5R)-5,6-dihydroxyhexyl 4-nitrobenzoate (prepared in Step 1)
(5.2 g, 9.2 mmol) in dichloromethane (30 mL) was added and the
reaction stirred at this temperature for 30 min. The crude mixture
was then poured on ice and the organic layer extracted, washed with
water, brine, dried over sodium sulfate, evaporated to give the
title compound as a pale yellow oil (6.8 g, 100%). The residue
obtained was used in the next step without further
purification.
[0420] 1H NMR (300 MHz, CDCl3) .delta. 8.32 (d, J=8.9 Hz, 2H),
8.26-8.15 (m, 2H), 5.39-5.25 (m, 1H), 4.78 (dd, J=12.9, 3.1 Hz,
1H), 4.52 (dd, J=12.9, 6.4 Hz, 1H), 4.46-4.35 (m, 2H), 1.97-1.77
(m, 4H), 1.77-1.49 (m, 2H).
Step 3: Synthesis of (2R)-6-hydroxyhexane-1,2-diyl dinitrate
[0421] To a stirred solution of (5R)-5,6-bis(nitrooxy)hexyl
4-nitrobenzoate (prepared in Step 2) (6.8 g, 18.2 mmol) in a 1/1
mixture of ethanol/THF (30 mL of each) at 0.degree. C., a 2M sodium
hydroxide solution (9.1 mL, 2 eq) was added and the reaction was
stirred for 2 h. The reaction was diluted with ethyl acetate and
water (100 mL of each) and extracted. The organic layer was
successively washed with water and brine, dried over sodium sulfate
and evaporated. The oily residue was purified by column
chromatography (SNAP 100, gradient system from 4/6 ethyl
acetate/n-hexane to 60/40 ethyl acetate/n-hexane) to give the title
compound as colorless oil (3.50 g, 86%).
[0422] 1H NMR (300 MHz, CDCl3) .delta. 5.32 (qd, J=6.7, 3.0 Hz,
1H), 4.77 (dd, J=12.9, 3.0 Hz, 1H), 4.49 (dd, J=12.9, 6.6 Hz, 1H),
3.68 (d, J=5.5 Hz, 2H), 1.89-1.71 (m, 2H), 1.70-1.48 (m, 5H), 1.46
(s, 1H).
Step 4: Synthesis of (R)-5,6-bis(nitrooxy)hexyl
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoate
[0423] To a stirred solution of
3-methyl-3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)butanoic
acid (237 mg; 0.95 mmol) (prepared as described in Example 1, steps
1 and 2) and (2R)-6-hydroxyhexane-1,2-diyl dinitrate (prepared in
Step 3) (213 mg; 0.95 mmol) in DCM (5 ml) cooled to 0.degree. C.,
EDAC (162 mg; 1.04 mmol) and a catalytic amount of DMAP were added.
The reaction was stirred overnight at 0.degree. C. The crude was
then washed with water, HCl 1N, water and brine, dried and
evaporated under vacuum. The crude was purified by flash
chromatography [Cy/EtOAc: 0% to 20% (1CV), 20% to 40% (7CV), 40% to
60% (2CV)] affording 338 mg of the title compound (Yield: 78.2%) as
a yellow oil.
[0424] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 5.30-5.21 (m, 1H),
4.74 (dd, J=12.9, 3.0 Hz, 1H), 4.47 (dd, J=12.9, 6.5 Hz, 1H), 3.99
(t, J=6.3 Hz, 2H), 2.98 (s, 2H), 2.16 (d, J=7.2 Hz, 3H), 1.96 (s,
6H), 1.81-1.69 (m, 2H), 1.66-1.56 (m, 2H), 1.52-1.31 (m, 8H).
.alpha..sub.D.sup.20=+2.3 (0.47% MeOH)
EXAMPLE 14
Synthesis of (S)-5,6-bis(nitrooxy)hexyl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e (Compound 17; (S)-isomer of compound 11)
##STR00054##
[0426] Step 1: Synthesis of
2,3-dimethoxy-5-methylbenzene-1,4-diol
##STR00055##
[0427] NaBH.sub.4 (5.2 g; 137.2 mmol) was dissolved in 150 ml of
water, and a solution of
2,3-dimethoxy-5-methylcyclohexa-2,5-diene-1,4-dione (Sg; 27.4 mmol)
in a mixture of 75 ml of Et.sub.2O and 38 ml of MeOH was added at
room temperature with stirring. After 15 min, the mixture was
placed in a separatory funnel, and the layers were allowed to
separate. The ether phase was removed and the aqueous phase was
extracted twice with 50 ml portions of ether. The combined organic
extracts were washed with brine and dried over Na.sub.2S0.sub.4.
Solvent removal under reduced pressure afforded the title compound
(9 g; 88%) as red oil. It was used in the next step without further
purification.
Step 2: Synthesis of
6-hydroxy-7,8-dimethoxy-4,4-dimethylchroman-2-one
##STR00056##
[0429] 2,3-dimethoxy-5-methylbenzene-1,4-diol (obtained in Step 2)
(9 g; 49 mmol), methyl 3-methylbut-2-enoate (7 ml; 58 mmol) and
methanesulfonic acid (80 mL) were heated at 70.degree. C. with
stirring for 90 min. Then the mixture was poured into ice then
diluted to 600 ml with water and extracted with diethyl ether
(3.times.150 ml). The combined organic layers were washed with
brine, dried over Na.sub.2SO.sub.4 and concentrated to dryness to
afford a brown solid, which was crystallized from methanol to
provide pure title compound (6.5 g; 50%) as yellow crystals.
Step 3: Synthesis of 4-nitrophenyl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e
##STR00057##
[0431] A synthetic procedure similar to the one described by
Carpino et al., J. Org. Chem., 1989, 54, 3303-3310 was used, but
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoic
acid, even if described in the paper, proved to be high unstable,
so it was converted in situ into its 4-nitrophenyl ester.
[0432] Lactone obtained in Step 3 (2 g; 7.51 mmol) in DMF (15 mL)
was added to a stirred solution of PDC (12.7 g; 33.7 mmol) in DMF
(15 mL) at room temperature, and stirring was continued for 4 h.
The mixture was diluted to 300 mL with water and extracted quickly
with diethyl ether (3.times.150 mL). The combined ether extracts
were washed with brine, dried over Na.sub.2SO.sub.4 and
concentrated to about 10 mL. This solution was diluted in EtOAc (40
mL) and then p-nitrophenol (1.57 g; 11.2 mmol), DCC (2.31 g; 11.2
mmol; 1.5 eq.) and DMAP (cat) were successively added. The mixture
was stirred at room temperature for 16 h, then it was concentrated
to dryness. Purification by chromatography on neutral alumina
(eluent: cyclohexane/AcOEt 8/2) led to the title compound (800 mg;
26%) as an orange oil.
[0433] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 8.24 (d, 2H), 7.20
(d, 2H), 3.93 (s, 3H), 3.89 (s, 3H), 3.32 (s, 2H), 2.19 (s, 3H),
1.55 (s, 3H), 1.53 (s, 3H).
Step 4: Synthesis of (S)-5,6-bis(nitrooxy)hexyl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e
##STR00058##
[0435] In a 50-ml one-necked flask, 178.0 mg (0.45 mmole) of
4-nitrophenyl
dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoate
(obtained in Step 4) and 111.0 mg (0.50 mmole) of
(S)-6-hydroxyhexane-1,2-diyl dinitrate (obtained in Example 12,
Step 2) were added to DCM (1.5 ml). After a 10 minutes 55.0 mg
(0.45 mmole) of DMAP were added. The solution was stirred for 18
hours to room temperature. The reaction was washed with water,
dried with MgSO.sub.4, filtered and concentrated under reduced
pressure to give red oil in a quantitative yield. The obtained red
oil was purified by automatic column chromatography using silica
gel Cy/DCM/MeOH (50/50/0 to 68/30/2) mixture as eluent to give 200
mg (91% yield) of the title compound as a orange oil.
[0436] MS: m/z=489 [M+H].sup.+
[0437] TLC: (Cy/DCM/MeOH 68:30:2) R.sub.f=0.33
[0438] NMR (CDCl.sub.3): 5.25 (m, 1H), 4.74 (dd, 1H), 4.50 (dd,
1H), 4.0 (t, 2H), 3.97 (s, 3H), 3.93 (s, 3H), 3.0 (s, 2H), 2.14 (s,
3H), 1.8-1.5 (m, 6H), 1.43 (s, 6H).
EXAMPLE 15
Synthesis of (S)-5,6-bis(nitrooxy)hexyl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e (Compound 17)
##STR00059##
[0439] the title compound was prepared as follow:
Step 1: Synthesis of 2,5-dioxopyrrolidin-1-yl
3-(4,5-dimethoxy-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoate
##STR00060##
[0441] A synthetic procedure similar to the one described by
Carpino et al., J. Org. Chem., 1989, 54, 3303-3310 was used, but
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoic
acid, even if described in the paper, proved to be high unstable,
so it was converted in situ into its N-hydroxysuccinimido
ester.
[0442] Lactone obtained in Example 14 Step 3 (2.5 g; 9.39 mmol) in
DMF (20 mL) was added to a stirred solution of PDC (14.8 g; 39.4
mmol) in DMF (20 mL) at room temperature, and stirring was
continued for 4 h. The mixture was diluted to 300 mL with water and
extracted quickly with diethyl ether (3.times.150 mL). The combined
ether extracts were washed with brine, dried over Na.sub.2SO.sub.4
and concentrated to about 10 mL. This solution was diluted in DCM
(40 mL) and NHS (1.29 g; 11.2 mmol) as well as EDCl.HCI (2.16 g;
11.2 mmol) were added successively and stirring was continued for
16 h. The mixture was diluted with water and extracted with DCM.
The combined organic layers were washed with brine, dried over
Na.sub.2SO.sub.4 and concentrated to dryness to afford the title
compound (2.74 g; 78%) as an orange oil.
[0443] .sup.1H NMR (300 MHz, CDCl.sub.3) .delta. 3.97 (s, 3H), 3.88
(s, 3H), 3.28 (s, 2H), 2.88 (s, 4H), 2.16 (s, 3H), 1.55 (s, 3H),
1.57 (s, 3H).
Step 2: Synthesis of (S)-5,6-bis(nitrooxy)hexyl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e (Compound 17)
[0444] A mixture of 40.0 mg (0.1 mmole) of 2,5-dioxopyrrolidin-1-yl
3-(4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dienyl)-3-methylbutanoat-
e, 28.0 mg (0.12 mmole) of (S)-6-hydroxyhexane-1,2-diyl dinitrate
(prepared in Example 12, Step 2) and DMF (1 ml) were mixed together
under stirring. After 10 minutes 19.0 mg (0.1 mmole) of EDC*HCl and
12.0 mg (0.1 mmole) of DMAP were added. The solution was stirred
for 5 hours to 50.degree. C. The reaction was washed with water,
dried with MgSO4, filtered and concentrated under reduced pressure
to give a red oil in a quantitative yield. The obtained red oil was
purified by automatic column chromatography using silica gel
Versaflash cartridges with Cy/DCM/MeOH (50/50/0 to 68/30/2) mixture
as eluent to give 14.6 mg (31% yield) of the title compound as a
orange oil.
[0445] MS: m/z=489 [M+H].sup.+
[0446] TLC: (Cy/DCM/MeOH 68:30:2) R.sub.f=0.33
[0447] NMR (CDCl.sub.3): 5.25 (m, 1H), 4.74 (dd, 1H), 4.50 (dd,
1H), 4.0 (t, 2H), 3.97 (s, 3H), 3.93 (s, 3H), 3.0 (s, 2H), 2.14 (s,
3H), 1.8-1.5 (m, 6H), 1.43 (s, 6H).
EXAMPLE 16
[0448] Intraocular pressure (TOP) lowering activity in hypertonic
saline-induced IOP increase in rabbits
[0449] The present study evaluated the intraocular pressure
lowering effect of single applications of two different
concentrations (1% and 0.3%) of compound (1) in rabbits with
experimental increase in IOP.
[0450] Adults male New Zealand White rabbits weighting 1.8-2.0 Kg
were used in the experiments.
[0451] The transient increase in IOP was induced by the injection
of 0.1 ml of hypertonic saline solution (5%) into the vitreous
bilaterally (Krauss et al., 2011, Orihashi et al., 2005).
[0452] IOP was measured using a Tono-Pen XL prior to hypertonic
saline injection (basal) and at 30, 60, 120 and 240 min thereafter.
Vehicle (5% cremophor-EL; 0.3% DMSO; 0.2 mg/ml Benzalkonium
chloride in PBS pH 6.0) or compound was instilled as eye drops
immediately after hypertonic saline injection. Eyes were randomly
assigned to different treatment groups. Vehicle and compound were
directly instilled into the conjunctiva pocket at the desired
doses. One drop of 0.4% oxybuprocaine hydrochloride (Novesine,
Sandoz) was instilled in each eye immediately before each set of
pressure measurements.
[0453] Results are reported in Table 3 and they are expressed as
IOP change (at 60 and 120 minutes following topical administration)
versus vehicle and versus IOP at basal before hypertonic saline
injection. Single application of both doses of compound (1)
resulted in a significant IOP reduction.
TABLE-US-00003 TABLE 3 Intraocular pressure (IOP) lowering effect
of compound (1) in hypertonic saline-induced IOP increase in
rabbits IOP change (mmHg) Dose 60 minutes 120 minutes 1% -9.1 .+-.
3.4 -9.5 .+-. 2.2 0.3% -5.5 .+-. 3.1 -5.7 .+-. 2.1
EXAMPLE 17
[0454] Intraocular pressure (TOP) lowering activity in hypertonic
saline-induced IOP increase in rabbits.
[0455] The present study evaluated the intraocular pressure
lowering effect of single application of compound (15) (Example 12)
and of ISMN (isosorbide-5-mononitrate) used as reference compound,
in an animal model of elevated IOP.
[0456] Adults male New Zealand White rabbits weighting 1.8-2.0 Kg
were used in the experiments.
[0457] Animals were anesthetized using 20 mg/ml/kg of sodium
pentobarbital. The increase in IOP was induced by the injection of
0.1 ml of hypertonic saline solution (5%) into the vitreous
bilaterally (Krauss et al., 2011, Orihashi et al., 2005).
[0458] IOP was measured using a Tono-Pen XL prior to hypertonic
saline injection (basal) and at 30, 60, 90, 120, 240 and 360 min
thereafter. Vehicle (5% cremophor-EL; 0.3% DMSO; 0.2 mg/ml
Benzalkonium chloride in PBS pH 6.0,) or tested compound was
instilled as eye drops immediately after hypertonic saline
injection. Eyes were randomly assigned to different treatment
groups. Vehicle or compounds were directly instilled into the
conjunctiva pocket at the desired doses. One drop of 0.2%
oxybuprocaine hydrochloride (Novesine, Sandoz) diluted 1:1 with
saline was instilled in each eye immediately before each set of
pressure measurements.
[0459] Results are reported in Table 4 and they are expressed as
IOP change (at 30 and 60 minutes following topical administration)
versus vehicle and versus IOP at basal before hypertonic saline
injection.
[0460] Single application of compound (15) resulted in a
significantly higher IOP reduction as compared to ISMN treated
group.
TABLE-US-00004 TABLE 4 Intraocular pressure (IOP) lowering effect
in hypertonic saline-induced IOP increase in rabbits IOP change
(mmHg) Compound/dose 30 minutes 60 minutes Compound (15) -6.5 .+-.
2.6 -4.9 .+-. 2.4 (1%) ISMN -2.6 .+-. 3.5 -0.7 .+-. 2.9 (1%)
* * * * *